Pronunciation: (klôr'ul, klōr'-),[key] —n. 1. Also called trichloroacetaldehyde, trichloroacetic acid aldehyde. a colorless, oily liquid, C2Cl3HO, 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 calledchlo'ral hy'drate.Pharm.a white, crystalline solid, C2H3Cl3O2, formed by combining liquid chloral with water: used as a hypnotic.