Emily Dickinson Lexicon

MULE, n. [Sp. and It. mulo; L. mulus; Sax. mul; D. muil or muilezel; G. maulesel; Sw. mulåsne; Dan. mule; Fr. id.; Arm. mules; Ir. muile; W. mul. The latter signifies a mule, and bashful, simple.]

1. A quadruped of a mongrel breed, usually generated between an ass and a mare, sometimes between a horse and a she-ass. But the name is applied to any animal produced by a mixture of different species. Encyc.
2. A plant or vegetable produced by impregnating the pistil of one species with the farin or fecundating dust of another. This is called also a hybrid. Encyc. Martyn.
3. An instrument used in spinning.