n. [ F. uréthane. See Urea; Ether. ] 1. (Org. Chem.) A white crystalline substance, NH2.CO.OC2H5, produced by the action of ammonia on ethyl carbonate or by heating urea nitrate and ethyl alcohol. It is used as a hypnotic, antipyretic, and antispasmodic. Hence, any ester of carbamic acid. [ Webster 1913 Suppl. ]