·noun A white crystalline substance, NH2·CO·OC2H5, produced by the action of ammonia on ethyl carbonate. It is used somewhat in medicine as a hypnotic. By extension, any one of the series of related substances of which urethane proper is the type.
II. Urethane ·add. ·noun A white crystalline substance, NH2·COOC2H5, 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.