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. 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 ]

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. [ 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 ]

a. Formed into a hydrate; combined with water. [ 1913 Webster ]

n. (Chem.) A compound, analogous to a hydrate, regarded as a salt of sulphydric acid, or as a derivative of hydrogen sulphide in which one half of the hydrogen is replaced by a base (as potassium sulphydrate, KSH), or as a hydrate in which the oxygen has been wholly or partially replaced by sulphur. [ 1913 Webster ]