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 C/nurus. See these words in the Vocabulary.

Resembling a hydatid.

Resembling water; watery; aqueous; hyaloid.

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.

Dipped in the gall of the fabulous hydra; poisonous; deadly.

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

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.

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

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.

An abnormally watery state of the blood; an/mia.

Causing a discharge of water; expelling serum effused into any part of the body, as in dropsy. A hydragogue medicine, usually a cathartic or diuretic.

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

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.

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

A natural family of plants including the hydrangeas, sometimes included in the family Saxifragaceae.

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

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

A compound of the bichloride of mercury with another chloride.

Of or pertaining to mercury; containing, or impregnated with, mercury.

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

Quicksilver; mercury.

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

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.

To form into a hydrate; to combine with water.

Formed into a hydrate; combined with water.

The act of becoming, or state of being, a hydrate.

Of or pertaining to hydraulics, or to fluids in motion; conveying, or acting by, water; as, an hydraulic clock, crane, or dock.

Hydraulic.

An ancient musical instrument played by the action of water; a water organ.

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.

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.

Same as Hydrocephaloid.

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.

A water nymph.

Pertaining to, or containing, hydrogen; as, hydric oxide.

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

Having the form or structure of a hydra.

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

Same as Hydriodide.

Pertaining to, or derived from, hydrogen and iodine; -- said of an acid (HI) produced by the combination of these elements.

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

A hydro-a/roplane.

Pertaining to, employed in, or produced by, the evolution of electricity by means of a battery in which water or steam is used.

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

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

A body formed from bilirubin, identical with urobilin.

A hydro-a/roplane having two supporting planes.

An extensive artificial division of gastropod mollusks, including those that breathe by gills, as contrasted with the Pulmonifera.

Same as Hydrobromide.

Composed of hydrogen and bromine; as, hydrobromic acid.

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

A compound containing only hydrogen and carbon, as methane, benzene, etc.; also, by extension, any of their derivatives.

Of the nature, or containing, hydrocarbons.

A hydrocarbon. A hydrous carbonate, as malachite.

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

Carbureted hydrogen; also, a hydrocarbon.

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

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.

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

Resembling hydrocephalus.

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.

Same as Hydrochloride.

Pertaining to, or compounded of, chlorine and hydrogen gas; as, hydrochloric acid; chlorhydric.

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

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.

See Hydrocyanide.

Pertaining to, or derived from the combination of, hydrogen and cyanogen.

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

Pertaining to, or derived from, the dynamical action of water of a liquid; of or pertaining to water power.

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.

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

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

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

A supposed compound of hydrofluoris acid and a base; a fluoride.

Pertaining to, or containing, hydrogen and fluorine; fluohydric; as, hydrofluoric acid.

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

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

Pertaining to, produced by, or consisting of, electricity evolved by the action or use of fluids; as, hydrogalvanic currents.

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.

To hydrogenize.

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

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

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

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

Of or pertaining to hydrogen; containing hydrogen.

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

The negative pole or cathode.

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.

Of or relating to hydrography.

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

A hydride.

Related to, or resembling, the hydra; of or pertaining to the Hydroidea. One of the Hydroideas.

An extensive order of Hydrozoa or Acaleph/.

Of or pertaining to the motions of fluids, or the forces which produce or affect such motions; -- opposed to hydrostatic.

an enzyme which causes the splitting of a chemical bond with the addition of the elements of water; a hydrolytic enzyme. Formerly called a hydrolytic ferment.

Of or pertaining to hydrology.

One skilled in hydrology.

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

A chemical process causing the splitting of a chemical bond by the addition of the elements of water. Where the bond which is split is not part of a ring structure, this process causes formation of two compounds from one compound plus water, as in the hydrolysis of the ester bonds of fats during saponification.

Tending to remove or separate water; eliminating water.

A hydrous carbonate of magnesia occurring in white, earthy, amorphous masses.

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

Of or pertaining to divination by water.

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

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

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

See Cyamellone.

Of or pertaining to hydrometallurgy; involving the use of liquid reagents in the treatment or reduction of ores.

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

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.

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

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

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

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

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

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

A variety of potash mica containing water. It is less elastic than ordinary muscovite.

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

A hydropathist.

Of or pertaining to hydropathy.