Amide \Am"ide\ (?; 277), n. [Ammonia + -ide.] (Chem.) A compound formed by the union of amidogen with an acid element or radical. It may also be regarded as ammonia in which one or more hydrogen atoms have been replaced by an acid atom or radical. [1913 Webster] {Acid amide}, a neutral compound formed by the substitution of the amido group for hydroxyl in an acid. [1913 Webster]