Leth"al (lĕth"ăl), n. [Lauric + ether + alcohol.] (Chem.) One of the higher alcohols of the paraffine series obtained from spermaceti as a white crystalline solid. It is so called because it occurs in the ethereal salt of lauric acid.

Le"thal (lē"thal), a. [L. lethalis, letalis, fr. lethum, letum, death: cf. F. léthal.] Deadly; mortal; fatal. "The lethal blow." W. Richardson. -- Le"thal*ly, adv.