the hinder part or buttocks of certain quadrupeds, especially of a horse; hence, the place behind the saddle.-an inflammatory affection of the larynx or trachea, accompanied by a hoarse, ringing cough and stridulous, difficult breathing; esp., such an affection when associated with the development of a false membrane in the air passages (also called membranous croup). see false croup, under false, and diphtheria.