a. [ Aëro- + hydrodynamic. ] Acting by the force of air and water; as, an aërohydrodynamic wheel. [ 1913 Webster ]

n. [ See Anhydrous. ] (Chem.) An oxide of a nonmetallic body or an organic radical, capable of forming an acid by uniting with the elements of water; -- so called because it may be formed from an acid by the abstraction of water. [ 1913 Webster ]

n. [ See Anhydrous. ] (Min.) A mineral of a white or a slightly bluish color, usually massive. It is anhydrous sulphate of lime, and differs from gypsum in not containing water (whence the name). [ 1913 Webster ]

a. [ Gr. &unr_; wanting water; 'an priv. + "y`dwr water.] Destitute of water; as, anhydrous salts or acids. [1913 Webster]

a. (Med.) Counteracting or preventing hydrophobia. -- n. A remedy for hydrophobia. [ 1913 Webster ]

a. (Med.) Good against dropsy. -- n. A remedy for dropsy. [ 1913 Webster ]

n. [ Pref. bi- + hydroguret. ] (Chem.) A compound of two atoms of hydrogen with some other substance. [ Obs. ] [ 1913 Webster ]

n. [ Carbon + hydrate. ] (Physiol. Chem.) One of a group of compounds including the sugars, starches, and gums, which contain six (or some multiple of six) carbon atoms, united with a variable number of hydrogen and oxygen atoms, but with the two latter always in proportion as to form water; as dextrose, C6H12O6. [ 1913 Webster ]

n. [ Carbon + hydrogen. ] (Chem.) A hydrocarbon. [ 1913 Webster ]

n. 1. a chemical substance (CCl3.CH(OH)2) which is a hydrate of trichloroacetaldehyde. It crystallizes as white monoclinic plates, obtained by treating chloral with water. It produces sleep when taken internally or hypodermically, and is used in medicine as a hypnotic and sedative; -- called also chloral It may be habit-forming, and is a controlled substance listed in the U. S. Code of Federal Regulations. It is sometimes used to render a person unconscious for illegal or nefarious purposes, and in this use, a concentrated solution is one of the agents called knockout drops. [ PJC ]

a. [ Chlorine + hydrogen + -ic. ] (Chem.) Same as Hydrochloric. [ 1913 Webster ]

n. (Chem.) One of a class of compounds formed from certain polybasic alcohols (and especially glycerin) by the substitution of chlorine for one or more hydroxyl groups. [ 1913 Webster ]

n. [ Conium + hydrate. ] (Chem.) A vegetable alkaloid found with conine in the poison hemlock (Conium maculatum). It is a white crystalline substance, C8H17NO, easily convertible into conine. [ 1913 Webster ]

n. [ Gr. kry`os cold + E. hydrate. ] (Chem.) A substance, as salt, ammonium chloride, etc., which crystallizes with water of crystallization only at low temperatures, or below the freezing point of water. F. Guthrie. [ 1913 Webster ]

v. t. To deprive of water; to render free from water; as, to dehydrate alcohol; to dehydrate food for preservation. [ 1913 Webster ]

v. i. 1. to lose water or moisture. [ PJC ]

2. to lose sufficent water to cause physiological distress; -- of living organisms; as, victims trapped in the earthquake rubble may dehydrate if not found quickly. [ PJC ]

adj. 1. thoroughly dried out.
Syn. -- desiccated, dried-out. [ WordNet 1.5 ]

2. suffering from fluid deprivation; as, to become deydrated from overexertion on a hot day. [ WordNet 1.5 ]

n. (Chem.) The act or process of freeing from water; also, the condition of a body from which the water has been removed. [ 1913 Webster ]

v. t. (Chem.) To deprive of, or free from, hydrogen. [ 1913 Webster ]

n. (Chem.) The act or process of freeing from hydrogen; also, the condition resulting from the removal of hydrogen. [ 1913 Webster ]

n. (Chem.) Same as Deutohydroguret.

n. [ Pref. deut-, deuto- + hydroguret. ] (Chem.) A compound containing in the molecule two atoms of hydrogen united with some other element or radical. [ Obs. ] [ 1913 Webster ]

‖n. [ NL. See Enhydrous. ] (Min.) A variety of chalcedony containing water. [ 1913 Webster ]

a. [ Gr. &unr_;; &unr_; in + &unr_; water. ] Having water within; containing fluid drops; -- said of certain crystals. [ 1913 Webster ]

n. an upright hydrant that can supply large volumes of water to use in fighting a fire. They are commonly placed at intervals at the street edge of a sidewalk, spaced for convenience in suppressing fires in towns.
Syn. -- fireplug, plug. [ WordNet 1.5 +PJC ]

a. [ Fluo- + hydrogen. ] (Chem.) See Hydrofluoric. [ 1913 Webster ]

See under Hydro-. [ 1913 Webster ]

{ . } 1. A combining form from Gr. &unr_;, &unr_;, water (see Hydra). [ 1913 Webster ]

2. (Chem.) A combining form of hydrogen, indicating hydrogen as an ingredient, as hydrochloric; or a reduction product obtained by hydrogen, as hydroquinone. [ 1913 Webster ]

n.; pl. E. Hydras L. Hydræ [ L. hydra, Gr. "y`dra; akin to "y`dwr water. See Otter the animal, Water. ] 1. (Class. Myth.) 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. [ 1913 Webster ]

Gorgons, and Hydras, and Chimeras dire. Milton. [ 1913 Webster ]

2. Hence: A multifarious evil, or an evil having many sources; not to be overcome by a single effort. [ 1913 Webster ]

3. (Zool.) Any small fresh-water hydroid of the genus Hydra, usually found attached to sticks, stones, etc., by a basal sucker. [ 1913 Webster ]

☞ 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. [ 1913 Webster ]

4. (Astron.) A southern constellation of great length lying southerly from Cancer, Leo, and Virgo. [ 1913 Webster ]

n. [ Hydr- + arachnid. ] (Zool.) An aquatic mite of the genus Hydrachna. The hydrachnids, while young, are parasitic on fresh-water mussels. [ 1913 Webster ]

n. [ Hydr- + acid: cf. F. hydracide. ] (Chem.) 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. [ 1913 Webster ]

a. [ Hydr- + acrylic. ] (Chem.) Pertaining to, or designating, an isomeric variety of lactic acid that breaks down into acrylic acid and water. [ 1913 Webster ]

n. [ See Hydra, and Actinia. ] (Zool.) 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. [ 1913 Webster ]

‖n. [ NL., fr. Gr. "y`dwr water + a"i^ma blood. ] (Med.) An abnormally watery state of the blood; anæmia. [ 1913 Webster ]

a. [ L. hydragogus conveying off water, Gr. &unr_;; "y`dwr water + &unr_; to lead: cf. F. hydragogue.] (Med.) Causing a discharge of water; expelling serum effused into any part of the body, as in dropsy. -- n. A hydragogue medicine, usually a cathartic or diuretic. [1913 Webster]

n. [ Hydr- + -amide. ] (Chem.) One of a group of crystalline bodies produced by the action of ammonia on certain aldehydes. [ 1913 Webster ]

n. [ Hydroxyl + amine. ] (Chem.) 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. [ 1913 Webster ]

peop. n. [ NL., fr. Gr. "y`dwr water + &unr_; vessel, capsule: cf. F. hydrangée.] (Bot.) 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. [1913 Webster]

prop. n. A natural family of plants including the hydrangeas, sometimes included in the family Saxifragaceae.
Syn. -- family Hydrangeaceae, hydrangea family. [ WordNet 1.5 ]

n. [ Gr. &unr_; to irrigate, fr. "y`dwr water. See Hydra.] A discharge pipe with a valve and spout at which water may be drawn from the mains of waterworks; a water plug. [1913 Webster]

n. [ Hydra + Gr. &unr_; a flower. ] (Zool.) One of the nutritive zooids of a hydroid colony. Also applied to the proboscis or manubrium of a hydroid medusa. See Illust. of Hydroidea. [ 1913 Webster ]

n. [ Hydrargyrum + chloride. ] (Chem.) A compound of the bichloride of mercury with another chloride. [ Obs. ] [ 1913 Webster ]

a. Of or pertaining to mercury; containing, or impregnated with, mercury. [ R. ] [ 1913 Webster ]

n. (Med.) A diseased condition produced by poisoning with hydrargyrum, or mercury; mercurialism. [ 1913 Webster ]

n. [ NL., fr. L. hydrargyrus, Gr. "ydra`rgyros; "y`dwr water + 'a`rgyros silver. ] (Chem.) Quicksilver; mercury. [ 1913 Webster ]

‖n. [ NL. See Hydro-, 1, and Arthrosis. ] (Med.) An effusion of watery liquid into the cavity of a joint. [ 1913 Webster ]

n. (Chem.) 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. [ 1913 Webster ]

a. Dipped in the gall of the fabulous hydra; poisonous; deadly. Cowper. [ 1913 Webster ]

n. [ 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. [1913 Webster]

v. t. [ imp. & p. p. Hydrated p. pr. & vb. n. Hydrating ] To form into a hydrate; to combine with water. [ 1913 Webster ]