Emily Dickinson Lexicon

ASS, n. [W. asyn; Ir. asan; L. asinus; Fr. âne, for asne; Arm. asen; Sp. Port. asno; It. asino. Qu. from Goth. auso, Gr. ους, an ear.]

1. A quadruped of the equine genus. This animal has long slouching ears, a short mane, and a tail covered with long hairs at the end. He is usually of an ash color, with a black bar across the shoulders. The tame or domestic ass is patient to stupidity, and carries a heavy burden. He is slow, but very sure footed, and for this reason very useful on rough steep hills.
2. A dull, heavy, stupid fellow; a dolt.