Chapter CCXIX: Foreword: Fore"word`, n (40)

HUSTINGS Hus"tings, n. pl. Etym: [OE. husting an assembly, coucil, AS. h; of Scand. origin; cf. Icel. h; h home + thing, assembly, meeting; akin to Dan. & Sw. ting, E. thing. See House, and Thing.]

1. A court formerly held in several cities of England; specif., a court held in London, before the lord mayor, recorder, and sheriffs, to determine certain classes of suits for the recovery of lands within the city. In the progress of law reform this court has become unimportant. Mozley & W.

2. Any one of the temporary courts held for the election of members of the British Parliament.

3. The platform on which candidates for Parliament formerly stood in addressing the electors. [Eng.] When the rotten hustings shake In another month to his brazen lies. Tennyson.

HUSTLE Hus"tle, v. t. [imp. & p. p. Hustled; p. pr. & vb. n. Hustling.] Etym: [D. hustelen to shake, fr. husten to shake. Cf. Hotchpotch.]

Defn: To shake together in confusion; to push, jostle, or crowd rudely; to handle roughly; as, to hustle a person out of a room. Macaulay.

HUSTLE Hus"tle, v. i.

Defn: To push or crows; to force one's way; to move hustily and with confusion; a hurry. Leaving the king, who had hustled along the floor with his dress worfully arrayed. Sir W. Scott.

HUSWIFE Hus"wife, n. Etym: [OE. huswif; hus house + wif wife. Cf. Hussy a housewife, Housewife.] [Written also housewife.]

1. A female housekeeper; a woman who manages domestic affairs; a thirfty woman. "The bounteous huswife Nature." Shak. The huswife is she that do labor doth fall. Tusser.

2. A worthless woman; a hussy. [Obs.] Shak.

3. Etym: [See Hussy a bag.]

Defn: A case for sewing materials. See Housewife. Cowper.

HUSWIFE Hus"wife, v. t.

Defn: To manage with frugality; -- said of a woman. Dryden.

HUSWIFELY Hus"wife*ly, a.

Defn: Like a huswife; capable; economical; prudent. -- adv.

Defn: In a huswifely manner.

HUSWIFERY Hus"wife*ry, n.

Defn: The business of a housewife; female domestic economy and skill. Tusser.

HUT Hut, n. Etym: [OE. hotte; akin to D. hut, G. hütte, OHG. hutta, Dan. hytte, Sw. hydda; and F. hutte, of G. origin; all akin to E. hide to conceal. See Hude to conceal.]

Defn: A small house, hivel, or cabin; a mean lodge or dwelling; a slightly built or temporary structure. Death comes on with equal footsteps To the hall and hut. Bp. Coxe.

HUTCH Hutch, v. t. & i. [imp. & p. p. Hutted; p. pr. & vb. n. Hutting.]

Defn: To place in huts; to live in huts; as, to hut troops in winter quarters. The troops hutted among the heights of Morristown. W. Irving.

HUTCH Hutch, n. Etym: [OE. hucche, huche, hoche, F. huche, LL. hutica.]

1. A chest, box, coffer, bin, coop, or the like, in which things may be stored, or animals kept; as, a grain hutch; a rabbit hutch.

2. A measure of two Winchester bushels.

3. (Mining)

Defn: The case of a flour bolt.

4. (Mining) (a) A car on low wheels, in which coal is drawn in the mine and hoisted out of the pit. (b) A jig for washing ore. Bolting hutch, Booby hutch, etc. See under Bolting, etc.

HUTCH Hutch, v. t. [imp. & p. p. Hutched; p. pr. & vb. n. Hutching.]

1. To hoard or lay up, in a chest. [R.] "She hutched the . . . ore." Milton.

2. (Mining)

Defn: To wash (ore) in a box or jig.

HUTCHUNSONIAN Hutch`un*so"ni*an, n.

Defn: A follower of John Hutchinson of Yorkshire, England, who believed that the Hebrew Scriptures contained a complete system of natural science and of theology.

HUTTONIAN Hut*to"ni*an, a.

Defn: Relating to what is now called the Plutonic theory of the earth, first advanced by Dr. James Hutton. Lyell.

HUTTONING Hut"ton*ing, n. [So named after two English bonesetters, Richard and Robert Hutton, who made it a part of their method.] (Med.)

Defn: Forcible manipulation of a dislocated, stiff, or painful joint.

HUXTER Hux"ter, n. & v. i.

Defn: See Huckster.

HUYGHENIAN Huy*ghe"ni*an, a.

Defn: Pertaining to, or invented by, Christian Huyghens, a Dutch astronomer of the seventeenth century; as, the Huyghenian telescope. Huyghenian eyepieceSee under Eyepiece.

HUZZ Huzz, v. i. Etym: [An onomatopoea. sq. root43. Cf. Buzz.]

Defn: To buzz; to murmur. [Obs.] Huzzing and burring in the preacher's ear. Latimer.

HUZZA Huz*za", interj. Etym: [Cf. G. hussa, husa, interj., hurrah, huzza. sq. root43. Cf. Hurrah.]

Defn: A word used as a shout of joy, exultation, approbation, or encouragement.

HUZZA Huz"za, n.

Defn: A shout of huzza; a cheer; a hurrah. They made a great huzza or shout. Evelyn.

HUZZA Huz*za", v. i. [imp. & p. p. Huzzaed; p. pr. & vb. n. Huzzaing.]

Defn: To shout huzza; to cheer.

HUZZA Huz*za", v. t.

Defn: To receive or attend with huzzas. He was huzzaed into the court. Addison.

HY Hy, a.

Defn: High. [Obs.] Chaucer.

HYACINE Hy"a*cine, n.

Defn: A hyacinth. [Obs.] Spenser.

HYACINTH Hy"a*cinth, n. Etym: [L. hyacinthus a kind of flower, prob. the iris, gladiolus, or larkspur, also a kind of gem, perh. the sapphire; as, a proper name, Hyacinthus, a beautiful Laconian youth, beloved by Apollo, fr. Gr. hyacinthe. Cf. Jacinth. The hyacinth was fabled to have sprung from the blood of Hyacinthus, who was accidentally slain by Apollo.]

1. (Bot.) (a) A bulbous plant of the genus Hyacinthus, bearing beautiful spikes of fragrant flowers. H. orientalis is a common variety. (b) A plant of the genus Camassia (C. Farseri), called also Eastern camass; wild hyacinth. (c) The name also given to Scilla Peruviana, a Mediterranean plant, one variety of which produces white, and another blue, flowers; -- called also, from a mistake as to its origin, Hyacinth of Peru.

2. (Min.)

Defn: A red variety of zircon, sometimes used as a gem. See Zircon. Hyacinth bean (Bot.), a climbing leguminous plant (Dolichos Lablab), related to the true bean. It has dark purple flowers and fruit.

HYACINTHIAN Hy`a*cin"thi*an, a.

Defn: Hyacinthine. [R.]

HYACINTHINE Hy`a*cin"thine, a. Etym: [L. hyacinthinus, Gr.

Defn: Belonging to the hyacinth; resemblingthe hyacinth; in color like the hyacinth. Milton. His curling locks like hyacinthine flowers. Cowper. The hyacinthine boy, for whom Morn well might break and April bloom. Emerson.

HYADES; HYADS Hy"a*des, Hy"ads, n.pl. Etym: [L. Hyades, Gr. (Astron.)

Defn: A cluster of five stars in the face of the constellation Taurus, supposed by the ancients to indicate the coming of rainy weather when they rose with the sun. Thro' scudding drifts the rainy Hyaned Vext the dim sea. Tennyson.

HYAENA Hy*æ"na, n. (Zoöl.)

Defn: Same as Hyena.

HYALEA Hy*a"le*a, n. Etym: [NL., fr. Gr. (Zoöl.)

Defn: A pteroid of the genus Cavolina. See Pteropoda, and Illustration in Appendix.

HYALESCENCE Hy`a*les"cence, n. Etym: [See Hyaline.]

Defn: The process of becoming, or the state of being, transparent like glass.

HYALINE Hy"a*line, a. Etym: [L. hyalinus, Gr. hyalin.]

Defn: Glassy; resembling glass; consisting of glass; transparent, like crystal. "Hyaline spaces." Carpenter.

HYALINE Hy"a*line, n.

1. A poetic term for the sea or the atmosphere. "The clear hyaline, the glassy sea." Milton. Our blood runs amazed 'neath the calm hyaline. Mrs. Browning.

2. (Biol.)

Defn: The pellucid substance, present in cells in process of development, from which, according to some embryologists, the cell nucleous originates.

3. (Physiol. Chem.)

Defn: The main constituent of the walls of hydatid cysts; a nitrogenous body, which, by decomposition, yields a dextrogyrate sugar, susceptible of alcoholic fermentation. Gamgee.

HYALITE Hy"a*lite, n. Etym: [Gr. hyalite.] (Min.)

Defn: A pellucid variety of opal in globules looking like colorless gum or resin; -- called also Müller's glass.

HYALOGRAPH Hy*al"o*graph, n. Etym: [Gr. graph.]

Defn: An instrument for tracing designs on glass.

HYALOGRAPHY Hy`a*log"ra*phy, n.

Defn: Art of writing or engraving on glass.

HYALOID Hy"a*loid, a. Etym: [Gr. hyaloïde.] (Anat.)

Defn: Resembling glass; vitriform; transparent; hyaline; as, the hyaloid membrane, a very delicate membrane inclosing the vitreous humor of the eye.

HYALONEMA Hy`a*lo*ne"ma, n. Etym: [NL., fr. Gr. (Zoöl.)

Defn: A genus of hexactinelline sponges, having a long stem composed of very long, slender, transparent, siliceous fibres twisted together like the strands of a color. The stem of the Japanese species (H. Sieboldii), called glass-rope, has long been in use as an ornament. See Glass-rope.

HYALOPHANE Hy*al"o*phane, n. Etym: [Gr. (Min.)

Defn: A species of the feldspar group containing barium. See Feldspar.

HYALOSPONGIA Hy`a*lo*spon"gi*a, n. pl. Etym: [NL., fr. Gr. (Zoöl.)

Defn: An order of vitreous sponges, having glassy six-rayed, siliceous spicules; -- called also Hexactinellinæ.

HYALOTYPE Hy*al"o*type, n. Etym: [Gr. -type.]

Defn: A photographic picture copied from the negative on glass; a photographic transparency. R. Hunt.

HYBERNACLE; HYBERNATE; HYBERNATION Hy*ber"na*cle, Hy"ber*nate, Hy`ber*na"tion.

Defn: See Hibernacle, Hibernate, Hibernation.

HYBLAEAN Hy*blæ"an, a. Etym: [L. Hyblaeus.]

Defn: Pertaining to Hybla, an ancient town of Sicily, famous for its bees.

HYBODONT Hyb"o*dont, a. Etym: [Gr. (Paleon.)

Defn: Of, pertaining to, or resembling, an extinct genus of sharks (Hybodus), especially in the form of the teeth, which consist of a principal median cone with smaller lateral ones.

HYBODUS Hyb"o*dus, n. Etym: [NL. See Hybodont.] (Paleon.)

Defn: An extinct genus of sharks having conical, compressed teeth.

HYBRID Hy"brid, n. Etym: [L. hybrida, hibrida, prob. allied to Gr. over: cf. F. hybride.] (Biol.)

Defn: The offspring of the union of two distinct species; an animal or plant produced from the mixture of two species. See Mongrel.

HYBRID Hy"brid, a.

Defn: Produced from the mixture of two species; as, plants of hybrid nature.

HYBRIDISM Hy"brid*ism, n.

Defn: The state or quality of being hybrid.

HYBRIDIST Hy"brid*ist, n.

Defn: One who hybridizes.

HYBRIDITY Hy*brid"i*ty, n.

Defn: Hybridism.

HYBRIDIZABLE Hy"brid*i`za*ble, a.

Defn: Capable of forming a hybrid, or of being subjected to a hybridizing process; capable of producing a hybrid by union with another species or stock. Hybridizable genera are rarer than is generally supposed, even in gardens where they are so often operated upon, under circumstances most favorable to the production of hybrids. J. D. Hooker.

HYBRIDIZATION Hy`brid*i*za"tion, n.

Defn: The act of hybridizing, or the state of being hybridized.

HYBRIDIZE Hy"brid*i`ze, v. t. [imp. & p. p. Hybridized; p. pr. & vb. n. Hybridizing.]

Defn: To render hybrid; to produce by mixture of stocks.

HYBRIDIZER Hy"brid*i`zer, n.

Defn: One who hybridizes.

HYBRIDOUS Hy"brid*ous, a.

Defn: Same as Hybrid.

HYDAGE Hyd"age, n. (Law)

Defn: A land tax. See Hidage.

HYDANTOIC Hy`dan*to"ic, a. (Chem.)

Defn: Pertaining to, or derived from, hydantoin. See Glycoluric.

HYDANTOIN Hy*dan"to*in, n. Etym: [Hydrogen + allantion.] (Chem.)

Defn: A derivative of urea, C3H4N2O2, obtained from allantion, as a white, crystalline substance, with a sweetish taste; -- called also glycolyl urea.

HYDATID Hy"da*tid, n. Etym: [Gr. "y`dwr, "y`datos, water: cf. F. hydatide.] (Zoöl.)

Defn: A membranous sac or bladder filled with a pellucid fluid, found in various parts of the bodies of animals, but unconnected with the tissues. It is usually formed by parasitic worms, esp. by larval tapeworms, as Echinococcus and Coenurus. See these words in the Vocabulary. Hydatid of Morgagni (Anat.), one of the small pedunculated bodies found between the testicle and the head of the epididymis, and supposed to be a remnant of the Müllerian duct.

HYDATIFORM Hy*dat"i*form, a. Etym: [Hydatid + -form.]

Defn: Resembling a hydatid.

HYDATOID Hy"da*toid, a. Etym: [Gr. "y`dwr, "y`datos, water + -oid.] (Anat.)

Defn: Resembling water; watery; aqueous; hyaloid.

HYDR- Hy"dr-

Defn: . See under Hydro-.

HYDRA Hy"dra, n.; pl. E. Hydras, L. Hydræ. Etym: [L. hydra, Gr. "y`dra; akin to "y`dwr water. See Otter the animal, Water.]

1. (Class. Myth.)

Defn: A serpent or monster in the lake or marsh of Lerna, in the Peloponnesus, represented as having many heads, one of which, when cut off, was immediately succeeded by two others, unless the wound was cauterized. It was slain by Hercules. Hence, a terrible monster. Gorgons, and Hydras, and Chimeras dire. Milton.

2. Hence: A multifarious evil, or an evil having many sources; not to be overcome by a single effort.

3. (Zoöl.)

Defn: Any small fresh-water hydroid of the genus Hydra, usually found attached to sticks, stones, etc., by a basal sucker.

Note: The body is a simple tube, having a mouth at one extremity, surrounded by a circle of tentacles with which it captures its prey. Young hydras bud out from the sides of the older ones, but soon become detached and are then like their parent. Hydras are remarkable for their power of repairing injuries; for if the body be divided in pieces, each piece will grow into a complete hydra, to which fact the name alludes. The zooids or hydranths of marine hydroids are sometimes called hydras.

4. (Astron.)

Defn: A southern constellation of great length lying southerly from Cancer, Leo, and Virgo.

HYDRACHNID Hy*drach"nid, n. Etym: [Hydr- + arachnid.] (Zoöl.)

Defn: An aquatic mite of the genus Hydrachna. The hydrachids, while young, are parasitic on fresh-water mussels.

HYDRACID Hy*drac"id, n. Etym: [Hydr- + acid: cf. F. hydracide.] (Chem.)

Defn: An acid containing hydrogen; -- sometimes applied to distinguish acids like hydrochloric, hydrofluoric, and the like, which contain no oxygen, from the oxygen acids or oxacids. See Acid.

HYDRACRYLIC Hy`dra*cryl"ic, a. Etym: [Hydr- + acrylic.] (Chem.)

Defn: Pertaining to, or designating, an isomeric variety of lastic acid that breaks down into acrylic acid and water.

HYDRACTINIAN Hy`drac*tin"i*an, n. Etym: [See Hydra, and Actinia.] (Zoöl.)

Defn: Any species or marine hydroids, of the genus Hydractinia and allied genera. These hydroids form, by their rootstalks, a firm, chitinous coating on shells and stones, and esp. on spiral shells occupied by hermit crabs. See Illust. of Athecata.

HYDRAEMIA Hy*dræ"mi*a, n. Etym: [NL., fr. Gr. "y`dwr water + (Med.)

Defn: An abnormally watery state of the blood; anæmia.

HYDRAGOGUE Hy"dra*gogue, a. Etym: [L. hydragogus conveying off water, Gr. "y`dwr water + hydragogue.] (Med.)

Defn: Causing a discharge of water; expelling serum effused into any part of the body, as in dropsy. -- n.

Defn: A hydragogue medicine, usually a cathartic or diuretic.

HYDRAMIDE Hy*dram"ide, n. Etym: [Hydr- + -amide.] (Chem.)

Defn: One of a group of crystalline bodies produced by the action of ammonia on certain aldehydes.

HYDRAMINE Hy*dram"ine, n. Etym: [Hydroxyl + amine.] (Chem.)

Defn: One of a series of artificial, organic bases, usually produced as thick viscous liquids by the action of ammonia on ethylene oxide. They have the properties both of alcohol and amines.

HYDRANGEA Hy*dran"ge*a, n. Etym: [NL., fr. Gr. "y`dwr water + hydrangée.] (Bot.)

Defn: A genus of shrubby plants bearing opposite leaves and large heads of showy flowers, white, or of various colors. H. hortensis, the common garden species, is a native of China or Japan.

HYDRANT Hy"drant, n. Etym: [Gr. "y`dwr water. See Hydra.]

Defn: A discharge pipe with a valve and spout at which water may be drawn from the mains of waterworks; a water plug.

HYDRANTH Hy"dranth, n. Etym: [Hydra + Gr. (Zoöl.)

Defn: One of the nutritive zooids of a hydroid colony. Also applied to the proboscis or manubrium of a hydroid medusa. See Illust. of Hydroidea.

HYDRARGOCHLORIDE Hy*drar"go*chlo"ride, n. Etym: [Hydrargyrum + chloride.] (Chem.)

Defn: A compound of the bichloride of mercury with another chloride. [Obs.]

HYDRARGYRATE Hy*drar"gy*rate, a.

Defn: Of or pertaining to mercury; containing, or impregnated with, mercury. [R.]

HYDRARGYRISM Hy*drar"gy*rism, n. (Med.)

Defn: A diseased condition produced by poisoning with hydrargyrum, or mercury; mercurialism.

HYDRARGYRUM Hy*drar"gy*rum, n. Etym: [NL., fr. L. hydrargyrus, Gr. (Chem.)

Defn: Quicksilver; mercury.

HYDRARTHROSIS Hy`drar*thro"sis, n. Etym: [NL. See Hydro-, 1, and Arthrosis.] (Med.)

Defn: An effusion of watery liquid into the cavity of a joint.

HYDRASTINE Hy*dras"tine, n. (Chem.)

Defn: An alkaloid, found in the rootstock of the golden seal (Hydrastis Canadensis), and extracted as a bitter, white, crystalline substance. It is used as a tonic and febrifuge.

HYDRA-TAINTED Hy"dra-taint`ed, a.

Defn: Dipped in the gall of the fabulous hydra; poisonous; deadly. Cowper.

HYDRATE Hy"drate, n. Etym: [Gr. "y`dwr water: cf. F. hydrate.] (Chem.) (a) A compound formed by the union of water with some other substance, generally forming a neutral body, as certain crystallized salts. (b) A substance which does not contain water as such, but has its constituents (hydrogen, oxygen, hydroxyl) so arranged that water may be eliminated; hence, a derivative of, or compound with, hydroxyl; hydroxide; as, ethyl hydrate, or common alcohol; calcium hydrate, or slaked lime.

HYDRATE Hy"drate, v. t. [imp. & p. p. Hydrated; p. pr. & vb. n. Hydrating.]

Defn: To form into a hydrate; to combine with water.

HYDRATED Hy"dra*ted, a.

Defn: Formed into a hydrate; combined with water.

HYDRATION Hy*dra"tion, n. (Chem.)

Defn: The act of becoming, or state of being, a hydrate. Water of hydration (Chem.), water chemically combined with some substance to form a hydrate; -- distinguished from water of crystallization.

HYDRAULIC Hy*drau"lic, a. Etym: [F. hydraulique, L. hydraulicus, fr. Gr. "y`dwr water + Hydra.]

Defn: Of or pertaining to hydraulics, or to fluids in motion; conveying, or acting by, water; as, an hydraulic clock, crane, or dock. Hydraulic accumulator, an accumulator for hydraulic machinery of any kind. See Accumulator, 2. -- Hydraulic brake, a cataract. See Cataract, 3. -- Hydraulic cement, a cement or mortar made of hydraulic lime, which will harden under water. -- Hydraulic elevator, a lift operated by the weight or pressure of water. -- Hydraulic jack. See under Jack. -- Hydraulic lime, quicklime obtained from hydraulic limestone, and used for cementing under water, etc. -- Hydraulic limestone, a limestone which contains some clay, and which yields a quicklime that will set, or form a firm, strong mass, under water. -- Hydraulic main (Gas Works), a horizontal pipe containing water at the bottom into which the ends of the pipes from the retorts dip, for passing the gas through water in order to remove ammonia. -- Hydraulic mining, a system of mining in which the force of a jet of water is used to wash down a bank of gold-bearing gravel or earth. [Pacific Coast] -- Hydraulic press, a hydrostatic press. See under Hydrostatic. -- Hydraulic propeller, a device for propelling ships by means of a stream of water ejected under water rearward from the ship. -- Hydraulic ram, a machine for raising water by means of the energy of the moving water of which a portion is to be raised. When the rush of water through the main pipe d shuts the valve at a, the momentum of the current thus suddenly checked forces part of it into the air chamber b, and up the pipe c, its return being prevented by a valve at the entrance to the air chamber, while the dropping of the valve a by its own weight allows another rush through the main pipe, and so on alternately. -- Hydraulic valve. (Mach.) (a) A valve for regulating the distribution of water in the cylinders of hydraulic elevators, cranes, etc. (b) (Gas Works) An inverted cup with a partition dipping into water, for opening or closing communication between two gas mains, the open ends of which protrude about the water.

HYDRAULICAL Hy*drau"lic*al, a.

Defn: Hydraulic.

HYDRAULICON Hy*drau"li*con, n. Etym: [NL. See Hydraulic.] (Mus.)

Defn: An ancient musical instrument played by the action of water; a water organ. [Written also hydraulis.]

HYDRAULICS Hy*drau"lics, n. Etym: [Cf. F. hydraulique.]

Defn: That branch of science, or of engineering, which treats of fluids in motion, especially of water, its action in rivers and canals, the works and machinery for conducting or raising it, its use as a prime mover, and the like.

Note: As a science, hydraulics includes hydrodynamics, or the principles of mechanics applicable to the motion of water; as a branch of engineering, it consists in the practical application of the mechanics of fluids to the control and management of water with reference to the wants of man, including canals, waterworks, hydraulic machines, pumps, water wheels, etc. Some writers treat hydraulics and hydrostatics as subdivisions of hydrodynamics.

HYDRAZINE Hy"dra*zine, n. Etym: [Hydr- + azo- + -ine.] (Chem.)

Defn: Any one of a series of nitrogenous bases, resembling the amines and produced by the reduction of certain nitroso and diazo compounds; as, methyl hydrazine, phenyl hydrazine, etc. They are derivatives of hydrazine proper, H2N.NH2, which is a doubled amido group, recently (1887) isolated as a stable, colorless gas, with a peculiar, irritating odor. As a base it forms distinct salts. Called also diamide, amidogen, (or more properly diamidogen), etc.

HYDRENCEPHSLOID Hy"dren*ceph"s*loid, a. Etym: [Hydrencephalus + -oid.] (Med.)

Defn: Same as Hydrocephaloid.

HYDRIA Hy"dri*a, n. Etym: [L., fr. Gr. (Gr. Antiq.)

Defn: A water jar; esp., one with a large rounded body, a small neck, and three handles. Some of the most beautiful Greek vases are of this form.

HYDRIAD Hy"dri*ad, n. Etym: [Gr. "y`dwr water.] (Myth.)

Defn: A water nymph.

HYDRIC Hy"dric, a. Etym: [From Hydrogen.] (Chem.)

Defn: Pertaining to, or containing, hydrogen; as, hydric oxide. Hydric dioxide. (Chem.) See Hydrogen dioxide, under Hydrogen. -- Hydric oxide (Chem.), water. -- Hydric sulphate (Chem.), hydrogen sulphate or sulphuric acid.

HYDRIDE Hy"dride, n. Etym: [Hydr- + ide.] (Chem.)

Defn: A compound of the binary type, in which hydrogen is united with some other element.

HYDRIFORM Hy"dri*form, a. Etym: [Hydra + -form.] (Zoöl.)

Defn: Having the form or structure of a hydra.

HYDRINA Hy*dri"na, n. pl. Etym: [NL. See Hydra.] (Zoöl.)

Defn: The group of hydroids to which the fresh-water hydras belong.

HYDRIODATE Hy*dri"o*date, n. Etym: [Cf. F. hydriodate.] (Zoöl.)

Defn: Same as Hydriodide.

HYDRIODIC Hy`dri*od"ic, a. Etym: [Hydr- + iodic: cf. F. hydriodique.] (Chem.)

Defn: Pertaining to, or derived from, hydrogen and iodine; -- said of an acid produced by the combination of these elements. Hydriodic acid (Chem.), a pungent, colorless gas, HI, usually prepared as a solution in water. It is strong reducing agent. Called also hydrogen iodine.

HYDRIODIDE Hy*dri"o*dide, n. (Chem.)

Defn: A compound of hydriodic acid with a base; -- distinguished from an iodide, in which only the iodine combines with the base.

HYDRO-; HYDR- Hy"dro-, Hy"dr-.

1. A combining form from Gr. Hydra).

2. (Chem.)

Defn: A combining form of hydrogen, indicating hydrogen as an ingredient, as hydrochloric; or a reduction product obtained by hydrogen, as hydroquinone.

HYDRO-AEROPLANE Hy"dro-a"ër*o*plane`. (Aëronautics)

Defn: An aëroplane with a boatlike or other understructure that enables it to travel on, or to rise from the surface of, a body of water by its own motive power.

HYDROBAROMETER Hy`dro*ba*rom"e*ter, n. Etym: [Hydro-, 1 + barometer.]

Defn: An instrument for determining the depth of the sea water by its pressure.

HYDROBILIRUBIN Hy`dro*bil`i*ru"bin, n. Etym: [Hydro-, 2 + bilirubin.] (Physiol. Chem.)

Defn: A body formed from bilirubin, identical with urobilin.

HYDROBIPLANE Hy"dro*bi"plane, n.

Defn: A hydro-aëroplane having two supporting planes.

HYDROBRANCHIATA Hy`dro*bran`chi*a"ta, n. pl. Etym: [NL., fr. Gr. "y`dwr water + (Zoöl.)

Defn: An extensive artificial division of gastropod mollusks, including those that breathe by gills, as contrasted with the Pulmonifera. -- Hy`dro*bran"chi*ate, a.

HYDROBROMATE Hy`dro*bro"mate, n. (Chem.)

Defn: Same as Hydrobromide.

HYDROBROMIC Hy`dro*bro"mic, a. Etym: [Hydro-, 2 + bromic.] (Chem.)

Defn: Composed of hydrogen and bromine; as, hydrobromic acid. Hydrobromic acid (Chem.), a colorless, pungent, corrosive gas, HBr, usually collected as a solution in water. It resembles hydrochloric acid, but is weaker and less stable. Called also hydrogen bromide.

HYDROBROMIDE Hy`dro*bro"mide, n. (Chem.)

Defn: A compound of hydrobromic acid with a base; -- distinguished from a bromide, in which only the bromine unites with the base.

HYDROCARBON Hy`dro*car"bon, n. Etym: [Hydro-, 2 + carbon.] (Chem.)

Defn: A compound containing only hydrogen and carbon, as methane, benzene, etc.; also, by extension, any of their derivatives. Hydrocarbon burner, furnace, stove, a burner, furnace, or stove with which liquid fuel, as petroleum, is used.

HYDROCARBONACEOUS Hy`dro*car`bo*na"ceous, a.

Defn: Of the nature, or containing, hydrocarbons.

HYDROCARBONATE Hy`dro*car"bon*ate, n. (a) (Old Chem.) A hydrocarbon. [Obs.] (b) (Chem.) A hydrous carbonate, as malachite.

HYDROCARBOSTYRIL Hy`dro*car`bo*sty"ril, n. Etym: [Hydro-, 2 + carbostyril.] (Chem.)

Defn: A white, crystalline, nitrogenous hydrocarbon, C9H9NO, obtained from certain derivatives of cinnamic acid and closely related to quinoline and carbostyril.

HYDROCARBURET Hy`dro*car"bu*ret, n. Etym: [Hydro-, 2 + carburet.] (Chem.)

Defn: Carbureted hydrogen; also, a hydrocarbon. [Obs.]

HYDROCAULUS Hy`dro*cau"lus, n.; pl. Hydrocauli. Etym: [NL., fr. Gr. "y`dwr water + (Zoöl.)

Defn: The hollow stem of a hydroid, either simple or branched. See Illust. of Gymnoblastea and Hydroidea.

HYDROCELE Hy`dro*cele, n. Etym: [L., fr. Gr. "y`dwr water + (Med.)

Defn: A collection of serous fluid in the areolar texture of the scrotum or in the coverings, especially in the serous sac, investing the testicle or the spermatic cord; dropsy of the testicle.

HYDROCEPHALIC Hy`dro*ce*phal"ic, a.

Defn: Relating to, or connected with, hydrocephalus, or dropsy of the brain.

HYDROCEPHALOID Hy`dro*ceph"a*loid, a. Etym: [Hydrocephalus + -oid.] (Med.)

Defn: Resembling hydrocephalus. Hydrocephaloid affection (Med.), the group of symptoms which follow exhausting diarrhea in young children, resembling those of acute hydrocephalus, or tubercular meningitis.

HYDROCEPHALOUS Hy`dro*ceph"a*lous, a.

Defn: Having hydrocephalus. "Hydrocephalous offspring." G. Eliot.

HYDROCEPHALUS Hy`dro*ceph"a*lus, n. Etym: [NL., fr. Gr. "y`dwr water + (Med.)

Defn: An accumulation of liquid within the cavity of the cranium, especially within the ventricles of the brain; dropsy of the brain. It is due usually to tubercular meningitis. When it occurs in infancy, it often enlarges the head enormously.

HYDROCHLORATE Hy`dro*chlo"rate, n. (Chem.)

Defn: Same as Hydrochloride.

HYDROCHLORIC Hy`dro*chlo"ric, a. Etym: [Hydro-, 2 + hloric: cf. F. hydrochlorique.] (Chem.)

Defn: Pertaining to, or compounded of, chlorine and hydrogen gas; as, hydrochloric acid; chlorhydric. Hydrochloric acid (Chem.), hydrogen chloride; a colorless, corrosive gas, HCl, of pungent, suffocating odor. It is made in great quantities in the soda process, by the action of sulphuric acid on common salt. It has a great affinity for water, and the commercial article is a strong solution of the gas in water. It is a typical acid, and is an indispensable agent in commercial and general chemical work. Called also muriatic, and chlorhydric, acid.

HYDROCHLORIDE Hy`dro*chlo"ride, n. (Chem.)

Defn: A compound of hydrochloric acid with a base; -- distinguished from a chloride, where only chlorine unites with the base.

HYDROCORALLIA Hy`dro*co*ral"li*a, n. pl. Etym: [NL. See Hydra, and Coral.] (Zoöl.)

Defn: A division of Hydroidea, including those genera that secrete a stony coral, as Millepora and Stylaster. Two forms of zooids in life project from small pores in the coral and resemble those of other hydroids. See Millepora.

HYDROCYANATE Hy`dro*cy"a*nate, n. (Chem.)

Defn: See Hydrocyanide.

HYDROCYANIC Hy`dro*cy*an"ic, a. Etym: [Hydro-, 2 + anic: cf. F. hydrocyanique.] (Chem.)

Defn: Pertaining to, or derived from the combination of, hydrogen and cyanogen. Hydrocyanic acid (Chem.), a colorless, mobile, volatile liquid, HCN, having a characteristic peach-blossom odor. It is one of the most deadly poisons. It is made by the action of sulphuric acid on yellow prussiate of potassium (potassium ferrocyanide), and chemically resembles hydrochloric and hydrobromic acids. Called also prussic acid, hydrogen cyanide, etc.

HYDROCYANIDE Hy`dro*cy"a*nide, n. (Chem.)

Defn: A compound of hydrocyanic acid with a base; -- distinguished from a cyanide, in which only the cyanogen so combines.

HYDRODYNAMIC; HYDRODYNAMICAL Hy`dro*dy*nam"ic, Hy`dro*dy*nam"ic*al, a. Etym: [Hydro-, 1 + dynamic, -ical: cf. F. hydrodynamique.]

Defn: Pertaining to, or derived from, the dynamical action of water of a liquid; of or pertaining to water power. Hydrodynamic friction, friction produced by the viscosity of a liquid in motion.

HYDRODYNAMICS Hy`dro*dy*nam"ics, n. Etym: [Hydro-, 1 + dynamics: cf. F. hydrodynamique.]

Defn: That branch of the science of mechanics which relates to fluids, or, as usually limited, which treats of the laws of motion and action of nonelastic fluids, whether as investigated mathematically, or by observation and experiment; the principles of dynamics, as applied to water and other fluids.

Note: The word is sometimes used as a general term, including both hydrostatics and hydraulics, together with pneumatics and acoustics. See Hydraulics.

HYDRODYNAMOMETER Hy`dro*dy`na*mom"e*ter, n. Etym: [Hydro-, 1 + dynamometer.]

Defn: An instrument to measure the velocity of a liquid current by the force of its impact.

HYDRO-ELECTRIC Hy`dro-e*lec"tric, a. Etym: [Hydro-, 1 + electric.]

Defn: Pertaining to, employed in, or produced by, the evolution of electricity by means of a battery in which water or steam is used. Hydro-electric machine (Physics), an apparatus invented by Sir William Armstrong of England for generating electricity by the escape of high-pressure steam from a series of jets connected with a strong boiler, in which the steam is produced.

HYDRO-EXTRACTOR Hy`dro-ex*tract"or, n. Etym: [Hydro-, 1 + extractor.]

Defn: An apparatus for drying anything, as yarn, cloth, sugar, etc., by centrifugal force; a centrifugal.

HYDROFERRICYANIC Hy`dro*fer`ri*cy*an"ic, n. Etym: [Hydro-, 2 + ferricyanic.] (Chem.)

Defn: Pertaining to, or containing, or obtained from, hydrogen, ferric iron, and cyanogen; as, hydroferricyanic acid. See Ferricyanic.

HYDROFERROCYANIC Hy`dro*fer`ro*cy*an"ic, a. Etym: [Hydro-, 2 + ferrocyanic.] (Chem.)

Defn: Pertaining to, or containing, or obtained from, hydrogen, ferrous iron, and cyanogen; as, hydroferrocyanic acid. See Ferrocyanic.

HYDROFLUATE Hy`dro*flu"ate, n. (Chem.)

Defn: A supposed compound of hydrofluoris acid and a base; a fluoride. [Archaic]

HYDROFLUORIC Hy`dro*flu*or"ic, a. Etym: [Hydro-, 2 + fluoric.] (Chem.)

Defn: Pertaining to, or containing, hydrogen and fluorine; fluohydric; as, hydrofluoric acid. Hydrofluoric acid (Chem.), a colorless, mobile, volatile liquid, HF, very corrosive in its action, and having a strong, pungent, suffocating odor. It is produced by the action of sulphuric acid on fluorite, and is usually collected as a solution in water. It attacks all silicates, as glass or porcelain, is the agent employed in etching glass, and is preserved only in vessels of platinum, lead, caoutchouc, or gutta-percha.

HYDROFLUOSILICATE Hy`dro*flu`o*sil"i*cate, n. (Chem.)

Defn: A salt of hydrofluosilic acid; a silicofluoride. See Silicofluoride.

HYDROFLUOSILICIC Hy`dro*flu`o*si*lic"ic, a. Etym: [Hydro-, 2 + fluorine + silicic.] (Chem.)

Defn: Pertaining to, or denoting, a compound consisting of a double fluoride of hydrogen and silicon; silicofluoric. See Silicofluoric.

HYDROGALVANIC Hy`dro*gal*van"ic, a. Etym: [Hydro-, 1 + galvanic.]

Defn: Pertaining to, produced by, or consisting of, electricity evolved by the action or use of fluids; as, hydrogalvanic currents. [R.]

HYDROGEN Hy"dro*gen, n. Etym: [Hydro-, 1 + -gen: cf. F. hydrogène. So called because water is generated by its combustion. See Hydra.] (Chem.)

Defn: A gaseous element, colorless, tasteless, and odorless, the lightest known substance, being fourteen and a half times lighter than air (hence its use in filling balloons), and over eleven thousand times lighter than water. It is very abundant, being an ingredient of water and of many other substances, especially those of animal or vegetable origin. It may by produced in many ways, but is chiefly obtained by the action of acids (as sulphuric) on metals, as zinc, iron, etc. It is very inflammable, and is an ingredient of coal gas and water gas. It is standard of chemical equivalents or combining weights, and also of valence, being the typical monad. Symbol H. Atomic weight 1.

Note: Although a gas, hydrogen is chemically similar to the metals in its nature, having the properties of a weak base. It is, in all acids, the base which is replaced by metals and basic radicals to form salts. Like all other gases, it is condensed by great cold and pressure to a liquid which freezes and solidifies by its own evaporation. It is absorbed in large quantities by certain metals (esp. palladium), forming alloy-like compounds; hence, in view of quasi-metallic nature, it is sometimes called hydrogenium. It is the typical reducing agent, as opposed to oxidizers, as oxygen, chlorine, etc. Bicarbureted hydrogen, an old name for ethylene. -- Carbureted hydrogen gas. See under Carbureted. -- Hydrogen dioxide, a thick, colorless liquid, H2O2, resembling water, but having a bitter, sour taste, produced by the action of acids on barium peroxide. It decomposes into water and oxygen, and is manufactured in large quantities for an oxidizing and bleaching agent. Called also oxygenated water. -- Hydrogen oxide, a chemical name for water, H -- Hydrogen sulphide, a colorless inflammable gas, H2S, having the characteristic odor of bad eggs, and found in many mineral springs. It is produced by the action of acids on metallic sulphides, and is an important chemical reagent. Called also sulphureted hydrogen.

HYDROGENATE Hy"dro*gen*ate, v. t. [imp. & p. p. Hydrogenated; p. pr. & vb. n. Hydrogenating.] (Chem.)

Defn: To hydrogenize.

HYDROGENATION Hy`dro*gen*a"tion, n. (Chem.)

Defn: The act of combining with hydrogen, or the state of being so combined.

HYDROGENIDE Hy"dro*gen*ide, n. (Chem.)

Defn: A binary compound containing hydrogen; a hydride. [R.] See Hydride.

HYDROGENIUM Hy`dro*ge"ni*um, n. Etym: [NL. See Hydrogen.] (Chem.)

Defn: Hydrogen; -- called also in view of its supposed metallic nature. Graham.

HYDROGENIZE Hy"dro*gen*ize, v. t. [imp. & p. p. Hydrogenized; p. pr. & vb. n. Hydrogenizing.] (Chem.)

Defn: To combine with hydrogen; to treat with, or subject to the action of, hydrogen; to reduce; -- contrasted with oxidize.

HYDROGENOUS Hy*drog"e*nous, a.

Defn: Of or pertaining to hydrogen; containing hydrogen.

HYDROGNOSY Hy*drog"no*sy, n. Etym: [Hydro-, 1 + Gr.

Defn: A treatise upon, or a history and description of, the water of the earth.

HYDROGODE Hy"drog*ode, n. Etym: [Hydrogen + Gr. (Elec.)

Defn: The negative pole or cathode. [R.]

HYDROGRAPHER Hy*drog"ra*pher, n.

Defn: One skilled in the hydrography; one who surveys, or draws maps or charts of, the sea, lakes, or other waters, with the adjacent shores; one who describes the sea or other waters. Boyle.

HYDROGRAPHIC; HYDROGRAPHICAL Hy`dro*graph"ic, Hy`dro*graph"ic*al, a.

Defn: Of or relating to hydrography.

HYDROGRAPHY Hy*drog"ra*phy, n. Etym: [Hydro-, 1 + -graphy: cf. F. hydrographie.]

1. The art of measuring and describing the sea, lakes, rivers, and other waters, with their phenomena.

2. That branch of surveying which embraces the determination of the contour of the bottom of a harbor or other sheet of water, the depth of soundings, the position of channels and shoals, with the construction of charts exhibiting these particulars.

HYDROGURET Hy*drog"u*ret, n. Etym: [From Hydrogen.] (Chem.)

Defn: A hydride. [Obs.]

HYDROID Hy"droid, a. Etym: [Hydra + -oid.] (Zoöl.)

Defn: Related to, or resembling, the hydra; of or pertaining to the Hydroidea. -- n.

Defn: One of the Hydroideas.

HYDROIDEA Hy*droi"de*a, n. pl. Etym: [NL. See Hydra, and -oid.] (Zoöl.)

Defn: An extensive order of Hydrozoa or Acalephæ. [Written also Hydroida.]

Note: This order includes the hydras and the free-swimming hydromedusæ, together with a great variety of marine attached hydroids, many of which grow up into large, elegantly branched forms, consisting of a vast number of zooids (hydranths, gonophores, etc.), united by hollow stems. All the zooids of a colony are produced from one primary zooid, by successive buddings. The Siphonophora have also been included in this order by some writers. See Gymnoblastea, Hydromedusa, Gonosome, Gonotheca.

HYDROKINETIC Hy`dro*ki*net"ic, a. Etym: [Hydro-, 1 + kinetic.]

Defn: Of or pertaining to the motions of fluids, or the forces which produce or affect such motions; -- opposed to hydrostatic. Sir W. Thomson.

HYDROLOGICAL Hy`dro*log"ic*al, a.

Defn: Of or pertaining to hydrology.

HYDROLOGIST Hy*drol"o*gist, n.

Defn: One skilled in hydrology.

HYDROLOGY Hy*drol"o*gy, n. Etym: [Hydro-, 1 + -logy: cf. F. hydrologie.]

Defn: The science of water, its properties, phenomena, and distribution over the earth's surface.

HYDROLYSIS Hy*drol"y*sis, n. [Hydro-, 1 + -lysis.] (Chem.)

Defn: A chemical process involving the addition of the elements of water.

HYDROLYTIC Hy`dro*lyt"ic, a. Etym: [Hydro-, 1 + Gr. (Chem.)

Defn: Tending to remove or separate water; eliminating water. Hydrolytic agents, such as sulphuric acid or caustic alkali. Encyc. Brit. Hydrolitic ferment (Physiol. Chem.), a ferment, enzyme, or chemical ferment, which acts only in the presence of water, and which causes the substance acted upon to take up a molecule of water. Thus, diastase of malt, ptyalin of saliva, and boiling dilute sulphuric acid all convert starch by hydration into dextrin and sugar. Nearly all of the digestive ferments are hydrolytic in their action.

HYDROMAGNESITE Hy`dro*mag"ne*site, n. Etym: [Hydro-, 1 + magnesite.] (Min.)

Defn: A hydrous carbonate of magnesia occurring in white, early, amorphous masses.

HYDROMANCY Hy"dro*man`cy, n. Etym: [Hydro-, 1 + -mancy: cf. F. hydromancie.]

Defn: Divination by means of water, -- practiced by the ancients.

HYDROMANTIC Hy`dro*man"tic, a. Etym: [Cf. F. hydromantique.]

Defn: Of or pertaining to divination by water.

HYDROMECHANICS Hy`dro*me*chan"ics, n. Etym: [Hydro-, 1 + mechanics.]

Defn: That branch of physics which treats of the mechanics of liquids, or of their laws of equilibrium and of motion.

HYDROMEDUSA Hy`dro*me*du"sa, n.; pl. Hydromedusæ. Etym: [NL. See Hydra, and Medusa.] (Zoöl.)

Defn: Any medusa or jellyfish which is produced by budding from a hydroid. They are called also Craspedota, and naked-eyed medusæ.

Note: Such medusæ are the reproductive zooids or gonophores, either male or female, of the hydroid from which they arise, whether they become free or remain attached to the hydroid colony. They in turn produce the eggs from which the hydroids are developed. The name is also applied to other similar medusæ which are not known to bud from a hydroid colony, and even to some which are known to develop directly from the eggs, but which in structure agree essentially with those produced from hydroids. See Hydroidea, and Gymnoblastea.

HYDROMEL Hy"dro*mel, n. Etym: [L. hydromel, hydromeli, Gr. hydromel.]

Defn: A liquor consisting of honey diluted in water, and after fermentation called mead.

HYDROMELLONIC Hy`dro*mel*lon"ic, a.

Defn: See Cyamellone.

HYDROMETALLURGICAL Hy`dro*met`al*lur"gic*al, a.

Defn: Of or pertaining to hydrometallurgy; involving the use of liquid reagents in the treatment or reduction of ores. -- Hy`dro*met`al*lur"gic*al*ly, adv.

HYDROMETALLURGY Hy`dro*met"al*lur`gy, n. Etym: [Hydro-, 1 + metallurgy.]

Defn: The art or process of assaying or reducing ores by means of liquid reagents.

HYDROMETEOR Hy`dro*me"te*or, n. Etym: [Hydro-, 1 + meteor.]

Defn: A meteor or atmospheric phenomenon dependent upon the vapor of water; -- in the pl., a general term for the whole aqueous phenomena of the atmosphere, as rain, snow, hail, etc. Nichol.

HYDROMETEOROLOGICAL Hy`dro*me`te*or`o*log"ic*al, a.

Defn: Of or pertaining to hydrometeorology, or to rain, clouds, storms, etc.

HYDROMETEOROLOGY Hy`dro*me`te*or*ol"o*gy, n. Etym: [Hydro-, 1 + meteorology.]

Defn: That branch of meteorology which relates to, or treats of, water in the atmosphere, or its phenomena, as rain, clouds, snow, hail, storms, etc.

HYDROMETER Hy*drom"e*ter, n. Etym: [Hydro-, 1 + -meter: cf. F. hydromètre.]

1. (Physics)

Defn: An instrument for determining the specific gravities of liquids, and thence the strength spirituous liquors, saline solutions, etc.

Note: It is usually made of glass with a graduated stem, and indicates the specific gravity of a liquid by the depth to which it sinks in it, the zero of the scale marking the depth to which it sinks in pure water. Extra weights are sometimes used to adapt the scale to liquids of different densities.

2. An instrument, variously constructed, used for measuring the velocity or discharge of water, as in rivers, from reservoirs, etc., and called by various specific names according to its construction or use, as tachometer, rheometer, hydrometer, pendulum, etc.; a current gauge.

HYDROMETRIC; HYDROMETRICAL Hy`dro*met"ric, Hy`dro*met"ric*al, a. Etym: [Cf. F. hydromètrique.]

1. Of or pertaining to an hydrometer, or to the determination of the specific gravity of fluids.

2. Of or pertaining to measurement of the velocity, discharge, etc., of running water.

3. Made by means of an hydrometer; as, hydrometric observations. Hydrometric pendulum, a species of hydrometer consisting of a hollow ball of ivory or metal suspended by a treated from the center of a graduated quadrant, and held in a stream to measure the velocity of the water by the inclination given to the thread; a kind of current gauge.

HYDROMETROGRAPH Hy`dro*met"ro*graph, n. Etym: [Hydro-, 1 + Gr. graph.]

Defn: An instrument for determining and recording the quantity of water discharged from a pipe, orifice, etc., in a given time.

HYDROMETRY Hy*drom"e*try, n. Etym: [Cf. F. hydromètrique.]

1. The art of determining the specific gravity of liquids, and thence the strength of spirituous liquors, saline solutions, etc.

2. The art or operation of measuring the velocity or discharge of running water, as in rivers, etc.

HYDROMICA Hy`dro*mi"ca, n. Etym: [Hydro-, 1 + mica.] (Min.)

Defn: A variety of potash mica containing water. It is less elastic than ordinary muscovite. Hydromica schist (Min.), a mica schist characterized by the presence of hydromica. It often has a silky luster and almost soapy feel.

HYDRONEPHROSIS Hy`dro*ne*phro"sis, n. Etym: [NL., Gr. "y`dwr water + (Med.)

Defn: An accumulation of urine in the pelvis of the kidney, occasioned by obstruction in the urinary passages.

HYDROPATH Hy"dro*path, n. Etym: [Cf. F. hydropathe.]

Defn: A hydropathist.

HYDROPATHIC; HYDROPATHICAL Hy`dro*path"ic, Hy`dro*path"ic*al, a.

Defn: Of or pertaining to hydropathy.

HYDROPATHIST Hy*drop"a*thist, n.

Defn: One who practices hydropathy; a water-cure doctor.

HYDROPATHY Hy*drop"a*thy, n. Etym: [Hydro-, 1 + Gr.

Defn: The water cure; a mode of treating diseases by the copious and frequent use of pure water, both internally and externally.

HYDROPERITONEUM Hy`dro*per`i*to*ne"um, n. Etym: [NL. See Hydro-, and Peritoneum.] (Med.)

Defn: Same as Ascites.

HYDROPHANE Hy"dro*phane, n. Etym: [Hydro-, 1 + Gr. hydrophane.] (Min.)

Defn: A semitranslucent variety of opal that becomes translucent or transparent on immersion in water.

HYDROPHANOUS Hy*droph"a*nous, a. (Min.)

Defn: Made transparent by immersion in water.

HYDROPHID Hy"dro*phid, n. Etym: [Hydro-, 1 + Gr. (Zoöl.)

Defn: Any sea snake of the genus Hydrophys and allied genera. These snakes are venomous, live upon fishes, and have a flattened tail for swimming.

HYDROPHLORONE Hy`dro*phlo"rone, n. Etym: [Hydro-, 2 + phlorone.] (Chem.)

Defn: A white, crystalline benzene derivative, C8H10O2, obtained by the reduction of phlorone.

HYDROPHOBIA Hy`dro*pho"bi*a, n. Etym: [L., fr. Gr. "y`dwr water + hydrophobie.] (Med.) (a) An abnormal dread of water, said to be a symptom of canine madness; hence: (b) The disease caused by a bite form, or inoculation with the saliva of, a rabid creature, of which the chief symptoms are, a sense of dryness and construction in the throat, causing difficulty in deglutition, and a marked heightening of reflex excitability, producing convulsions whenever the patient attempts to swallow, or is disturbed in any way, as by the sight or sound of water; rabies; canine madness. [Written also hydrophoby.]

HYDROPHOBIC Hy`dro*phob"ic, a. Etym: [L. hydrophobicus, Gr. hydrophobique.]

Defn: Of or pertaining to hydrophobia; producing or caused by rabies; as, hydrophobic symptoms; the hydrophobic poison.

HYDROPHOBY Hy"dro*pho`by, n.

Defn: See Hydrophobia.

HYDROPHORA Hy*droph"o*ra, n. pl. Etym: [NL., fr. E. hydra + Gr. (Zoöl.)

Defn: The Hydroidea.

HYDROPHORE Hy"dro*phore, n. Etym: [Gr. "y`dwr water +

Defn: An instrument used for the purpose of obtaining specimens of water from any desired depth, as in a river, a lake, or the ocean.

HYDROPHYLLIUM Hy`dro*phyl"li*um, n.; pl. L. Hydrophyllia, E. Hydrophylliums. Etym: [NL., fr. Gr. "y`dwr water + (Zoöl.)

Defn: One of the flat, leaflike, protective zooids, covering other zooids of certain Siphonophora.

HYDROPHYTE Hy"dro*phyte, n. Etym: [Gr. hydrophyte.]

Defn: An aquatic plant; an alga.

HYDROPHYTOLOGY Hy*droph`y*tol"o*gy, n. Etym: [Hydro- + phyte + -logy.]

Defn: The branch of botany which treats of water plants.

HYDROPIC; HYDROPICAL Hy*drop"ic, Hy*drop"ic*al, a. Etym: [L. hydropicus, Gr. hydropique. See Dropsy.]

Defn: Dropsical, or resembling dropsy. Every lust is a kind of hydropic distemper, and the more we drink the more we shall thirst. Tillotson.

HYDROPICALLY Hy*drop"ic*al*ly, adv.

Defn: In a hydropical manner.

HYDROPIPER Hy"dro*pi`per, n. Etym: [NL., fr. Gr. "y`dwr water + L. piper a pepper.] (Bot.)

Defn: A species (Polygonum Hydropiper) of knotweed with acrid foliage; water pepper; smartweed.

HYDROPLANE Hy"dro*plane, n. [Pref. hydro-, 1 + plane.]

1. A plane, or any of a number of planes, projecting from the hull of a submarine boat, which by being elevated or depressed cause the boat, when going ahead, to sink or rise, after the manner of an aëroplane.

2. A projecting plane or fin on a gliding boat to lift the moving boat on top of the water; also, a gliding boat.

HYDROPLANE Hy"dro*plane, v. i.

Defn: Of a boat, to plane (see Plane, below).

HYDROPNEUMATIC Hy`dro*pneu*mat"ic, a. Etym: [Hydro-, 1 + pneumatic: cf. F. hydropneumatique.]

Defn: Pertaining to, or depending upon, both liquid and gaseous substances; as, hydropneumatic apparatus for collecting gases over water or other liquids.

HYDROPNEUMATIC GUN CARRIAGE Hy`dro*pneu*mat"ic gun carriage. (Ordnance)

Defn: A disappearing gun carriage in which the recoil is checked by cylinders containing liquid and air, the air when compressed furnishing the power for restoring the gun to the firing position. It is used with some English and European heavy guns.

HYDROPSY Hy"drop`sy, n.

Defn: Same as Dropsy.

HYDROPULT Hy"dro*pult, n. Etym: [Hydro-, 1 + Gr.

Defn: A machine for throwing water by hand power, as a garden engine, a fire extinguisher, etc.

HYDROQUINONE Hy`dro*qui"none, n. Etym: [Hydro-, 2 + quinone.] (Chem.)

Defn: A white crystalline substance, C6H4(OH)2, obtained by the reduction of quinone. It is a diacid phenol, resembling, and metameric with, pyrocatechin and resorcin. Called also dihydroxy benzene.

HYDRORHIZA Hy`dro*rhi"za, n.; pl. L. Hydrorhizæ, E. Hydrorhizas. Etym: [NL., fr. E. hydra + Gr. (Zoöl.)

Defn: The rootstock or decumbent stem by which a hydroid is attached to other objects. See Illust. under Hydroidea.

HYDROSALT Hy"dro*salt`, n. Etym: [Hydro-, 1 + salt.] (Chem.) (a) A salt supposed to be formed by a hydracid and a base. (b) An acid salt. [R.] (c) A hydrous salt; a salt combined with water of hydration or crystallization.

HYDROSCOPE Hy"dro*scope, n. Etym: [Hydro-, 1 + -scope.]

1. An instrument designed to mark the presence of water, especially in air. Weale.

2. A kind of water clock, used anciently for measuring time, the water tricking from an orifice at the end of a graduated tube.

HYDROSOME; HYDROSOMA Hy"dro*some, Hy`dro*so"ma, n. Etym: [NL. hydrosoma. See Hydra, and - some body.] (Zoöl.)

Defn: All the zooids of a hydroid colony collectively, including the nutritive and reproductive zooids, and often other kinds.

HYDROSORBIC Hy`dro*sor"bic, a. Etym: [Hydro-, 2 + sorbic.] (Chem.)

Defn: Pertaining to, or designating, an acid obtained from sorbic acid when this takes up hydrogen; as, hydrosorbic acid.

HYDROSPHERE Hy"dro*sphere, n. [Pref. hydro-, 1 + sphere.]

1. (Meteor.)

Defn: The aqueous vapor of the entire atmosphere.

2. (Phys. Geog.) The aqueous envelope of the earth, including the ocean, all lakes, streams, and underground waters, and the aqueous vapor in the atmosphere.

HYDROSTAT Hy"dro*stat, n.

Defn: A contrivance or apparatus to prevent the explosion of steam boilers.

HYDROSTATIC; HYDROSTATICAL Hy`dro*stat"ic, Hy`dro*stat"ic*al, a. Etym: [Hydro-, 1 + Gr. hydrostatique. See Static.]

Defn: Of or relating to hydrostatics; pertaining to, or in accordance with, the principles of the equilibrium of fluids. The first discovery made in hydrostatics since the time of Archimedes is due to Stevinus. Hallam. Hydrostatic balance, a balance for weighing substances in water, for the purpose of ascertaining their specific gravities. -- Hydrostatic bed, a water bed. -- Hydrostatic bellows, an apparatus consisting of a water-tight bellowslike case with a long, upright tube, into which water may be poured to illustrate the hydrostatic paradox. -- Hydrostatic paradox, the proposition in hydrostatics that any quantity of water, however small, may be made to counterbalance any weight, however great; or the law of the equality of pressure of fluids in all directions. -- Hydrostatic press, a machine in which great force, with slow motion, is communicated to a large plunger by means of water forced into the cylinder in which it moves, by a forcing pump of small diameter, to which the power is applied, the principle involved being the same as in the hydrostatic bellows. Also called hydraulic press, and Bramah press. In the illustration, a is a pump with a small plunger b, which forces the water into the cylinder c, thus driving upward the large plunder d, which performs the reduced work, such as compressing cotton bales, etc.

HYDROSTATICALLY Hy`dro*stat"ic*al*ly, adv.

Defn: According to hydrostatics, or to hydrostatic principles. Bentley.

HYDROSTATICIAN Hy`dro*sta*ti"cian, n.

Defn: One who is versed or skilled in hydrostatics. [R.]

HYDROSTATICS Hy`dro*stat"ics, n. Etym: [Cf. F. hydrostatique.] (Physics)

Defn: The branch of science which relates to the pressure and equilibrium of nonelastic fluids, as water, mercury, etc.; the principles of statics applied to water and other liquids.

HYDROSULPHATE Hy`dro*sul"phate, n. (Chem.)

Defn: Same as Hydrosulphurent.

HYDROSULPHIDE Hy`dro*sul"phide, n. (Chem.)

Defn: One of a series of compounds, derived from hydrogen sulphide by the replacement of half its hydrogen by a base or basic radical; as, potassium hydrosulphide, KSH. The hydrosulphides are analogous to the hydrates and include the mercaptans.

HYDROSULPHITE Hy`dro*sul"phite, n. (Chem.)

Defn: A saline compound of hydrosulphurous acid and a base. [R.]

HYDROSULPHURET Hy`dro*sul"phu*ret, n. (Chem.)

Defn: A hydrosulphide. [Archaic]

HYDROSULPHURETED Hy`dro*sul"phu*ret`ed, a. (Chem.)

Defn: Combined with hydrogen sulphide.

HYDROSULPHURIC Hy`dro*sul*phu"ric, a. Etym: [Hydro-, 2 + sulphuric.] (Chem.)

Defn: Pertaining to, or derived from, hydrogen and sulphur; as, hydrosulphuricacid, a designation applied to the solution of hydrogen sulphide in water.

HYDROSULPHUROUS Hy`dro*sul"phur*ous, a. (Chem.)

Defn: Pertaining to, or designating, an acid obtained by the reduction of sulphurous acid. See Hyposulphurous acid, under Hyposulphurous.

HYDROTELLURATE Hy`dro*tel"lu*rate, n. (Chem.)

Defn: A salt formed by the union of hydrotelluric acid and the base.

HYDROTELLURIC Hy`dro*tel*lu"ric, a. Etym: [Hydro-, 2 + telluric.] (Chem.)

Defn: Formed by hydrogen and tellurium; as, hydrotelluric acid, or hydrogen telluride.

HYDROTHECA Hy`dro*the"ca, n.; pl. L. Hydrothecæ, E. Hydrothecas. Etym: [NL., fr. E. hydra + Gr. (Zoöl.)

Defn: One of the calicles which, in some Hydroidea (Thecaphora), protect the hydrants. See Illust. of Hydroidea, and Campanularian.

HYDROTHERAPEUTICS Hy`dro*ther`a*peu"tics, n. [Hydro-, 1 + therapeutics.] (Med.)

Defn: A system of treating disease by baths and mineral waters.

HYDROTHERAPY Hy`dro*ther"a*py, n. Etym: [Hydro-, 1 + therapy.] (Med.)

Defn: See Hydropathy.

HYDROTHERMAL Hy`dro*ther"mal, a. Etym: [Hydro-, 1 + thermal.]

Defn: Of or pertaining to hot water; -- used esp. with reference to the action of heated waters in dissolving, redepositing, and otherwise producing mineral changes within the crust of the globe.

HYDROTHORAX Hy`dro*tho"rax, n. Etym: [Hydro-, 1 + thorax.] (Med.)

Defn: An accumulation of serous fluid in the cavity of the chest.

HYDROTIC Hy*drot"ic, a. Etym: [Gr. "y`dwr water: cf. Gr. hydrotique.]

Defn: Causing a discharge of water or phlegm. -- n. (Med.)

Defn: A hydrotic medicine.

HYDROTICAL Hy*drot"ic*al, a.

Defn: Hydrotic.

HYDROTROPE Hy"dro*trope, n. Etym: [Hydro-, 1 + Gr.

Defn: A device for raising water by the direct action of steam; a pulsometer.

HYDROTROPIC Hy`dro*trop"ic, a. Etym: [See Hydrotrope.] (Bot.)

Defn: Turning or bending towards moisture, as roots.

HYDROTROPISM Hy*drot"ro*pism, n. (Bot.)

Defn: A tendency towards moisture.

HYDROUS Hy"drous, a. Etym: [Gr. "y`dwr water.]

1. Containing water; watery.

2. (Chem.)

Defn: Containing water of hydration or crystallization.

HYDROXANTHANE Hy`dro*xan"thane, n. (Chem.)

Defn: A persulphocyanate. [Obs.]

HYDROXANTHIC Hy`dro*xan"thic, a. Etym: [Hydro-, 2 + xanthic.] (Chem.)

Defn: Persulphocyanic.

HYDROXIDE Hy*drox"ide, n. Etym: [Hydro-, 2 + oxide.] (Chem.)

Defn: A hydrate; a substance containing hydrogen and oxygen, made by combining water with an oxide, and yielding water by elimination. The hydroxides are regarded as compounds of hydroxyl, united usually with basic element or radical; as, calcium hydroxide ethyl hydroxide.

HYDROXY- Hy*drox"y-. (Chem.)

Defn: A combining form, also used adjectively, indicating hydroxyl as an ingredient. Hydroxy acid (Chem.), an organic acid, having (besides the hydroxyl group of the carboxyl radical) an alcoholic hydroxyl group, and thus having the qualities of an alcohol in addition to its acid properties; as, lactic and tartaric acids are hydroxy acids.

HYDROXYL Hy*drox"yl, n. Etym: [Hydro-, 2 + oxygen + -yl.] (Chem.)

Defn: A compound radical, or unsaturated group, HO, consisting of one atom of hydrogen and one of oxygen. It is a characteristic part of the hydrates, the alcohols, the oxygen acids, etc.

HYDROXYLAMINE Hy*drox`yl*am"ine, n. Etym: [Hydroxyl + amine.] (Chem.)

Defn: A nitrogenous, organic base, NH2.OH, resembling ammonia, and produced by a modified reduction of nitric acid. It is usually obtained as a volatile, unstable solution in water. It acts as a strong reducing agent.

HYDROZOA Hy`dro*zo"a, n. pl. Etym: [NL., fr. E. hydra + Gr. (Zoöl.)

Defn: The Acalephæ; one of the classes of coelenterates, including the Hydroidea, Discophora, and Siphonophora.

HYDROZOAL Hy`dro*zo"al, a. (Zoöl.)

Defn: Of or pertaining to the Hydrozoa.

HYDROZOON; HYDROZOOEN Hy`dro*zo"ön, n.; pl. L. Hydrozoa, E. Hydrozoöns. Etym: [NL.] (Zoöl.)

Defn: One of the Hydrozoa.

HYDRURET Hy"dru*ret, n. Etym: [Hydro-, 2] (Chem.)

Defn: A binary compound of hydrogen; a hydride. [Obs.]

HYDRUS Hy"drus, n. Etym: [L., a water serpent; also, a certain constellation, Gr. "y`dros.] (Astron.)

Defn: A constellation of the southern hemisphere, near the south pole.

HYE Hye, n. & v.

Defn: See Hie. [Obs.] Chaucer.

HYEMAL Hy*e"mal, a. Etym: [L. hyemalis, or better hiemalis, fr. hyems, hiems, winter: cf. F. hyémal.]

Defn: Belonging to winter; done in winter. Sir T. Browne.

HYEMATE Hy"e*mate, v. i. Etym: [L. hiemare, hiematum. See Hyemal.]

Defn: To pass the winter. [Obs. & R.]

HYEMATION Hy`e*ma"tion, n. Etym: [L. hiematio.]

1. The passing of a winter in a particular place; a wintering.

2. The act of affording shelter in winter. [Obs.]

HYEN Hy"en, n. Etym: [F. hyène.]

Defn: A hyena. [Obs.] Shak.

HYENA Hy*e"na, n.; pl. Hyenas. Etym: [L. hyaena, Gr. hyène. See Sow female hog.] (Zoöl.)

Defn: Any carnivorous mammal of the family Hyænidæ, of which three living species are known. They are large and strong, but cowardly. They feed chiefly on carrion, and are nocturnal in their habits. [Written also hyæna.]

Note: The striped hyena (Hyæna striata) inhabits Southern Asia and a large part of Africa. The brown hyena (H. brunnea), and the spotted hyena (Crocuta maculata), are found in Southern Africa. The extinct cave hyena (H. spelæa) inhabited England and France. Cave hyena. See under Cave. -- Hyena dog (Zoöl.), a South African canine animal (Lycaon venaticus), which hunts in packs, chiefly at night. It is smaller than the common wolf, with very large, erect ears, and a bushy tail. Its color is reddish or yellowish brown, blotched with black and white. Called also hunting dog.

HYETAL Hy"e*tal, a. Etym: [Gr.

Defn: Of or pertaining to rain; descriptive of the distribution of rain, or of rainy regions.

HYETOGRAPH Hy"e*to*graph, n. Etym: [Gr. -graph.]

Defn: A chart or graphic representation of the average distribution of rain over the surface of the earth.

HYETOGRAPHIC Hy`e*to*graph"ic, a.

Defn: Of or pertaining to to hyetography.

HYETOGRAPHY Hy`e*tog"ra*phy, n.

Defn: The branch of physical science which treats of the geographical distribution of rain.

HYETOLOGY Hy`e*tol"o*gy, n. [Gr. + rain -logy.]

Defn: The science which treats of the precipitation of rain, snow, etc. -- Hy`e*to*log"ic*al, a.

HYGEIA Hy*ge"ia, n. Etym: [L. Hygea, Hygia, fr. Gr. (Classic Myth.)

Defn: The goddess of health, daughter of Esculapius.

HYGEIAN Hy*ge"ian, a.

Defn: Relating to Hygeia, the goddess of health; of or pertaining to health, or its preservation.

HYGEIST Hy"ge*ist, n.

Defn: One skilled in hygiena; a hygienist.

HYGIEIST Hy"gie*ist, n.

Defn: A hygienist.

HYGIENE Hy"gi*ene, n. Etym: [F. hygiène. See Hygeia.]