Urethane \U*reth"ane\, n. [F. ur['e]thane. 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.] 2. same as {polyurethane}. [PJC]