/klawr"euhl, klohr"-/ , n.
1. Also called trichloroacetaldehyde, trichloroacetic acid aldehyde . a colorless, oily liquid, C 2 Cl 3 HO, having a pungent odor, usually derived by the chlorination of ethyl alcohol or of acetaldehyde and combining with water to form chloral hydrate.
2. Also called chloral hydrate . Pharm. a white, crystalline solid, C 2 H 3 Cl 3 O 2 , formed by combining liquid chloral with water: used as a hypnotic.
[ 1825-35; CHLOR- 2 + -AL 3 ]