Mule

n. [ F., a she-mule, L. mula, fem. of mulus; cf. Gr. my`klos, mychlo`s. Cf. AS. mūl, fr. L. mulus. Cf. Mulatto. ] 1. (Zool.) A hybrid animal; specifically, one generated between an ass and a mare. Sometimes the term is applied to the offspring of a horse and a she-ass, but that hybrid is more properly termed a hinny. See Hinny. [ 1913 Webster ]

☞ Mules are much used as draught animals. They are hardy, and proverbial for stubbornness. [ 1913 Webster ]

2. (Bot.) A plant or vegetable produced by impregnating the pistil of one species with the pollen or fecundating dust of another; -- called also hybrid. [ 1913 Webster ]

3. A very stubborn person. [ 1913 Webster ]

4. A machine, used in factories, for spinning cotton, wool, etc., into yarn or thread and winding it into cops; -- called also jenny and mule-jenny. [ 1913 Webster ]

5. A slipper that has no fitting around the heel.
Syn. -- mules, scuff, scuffs. [ WordNet 1.5 ]

Mule armadillo (Zool.), a long-eared armadillo (Tatusia hybrida), native of Buenos Ayres; -- called also mulita. See Illust. under Armadillo. --
Mule deer (Zool.), a large deer (Cervus macrotis syn. Cariacus macrotis) of the Western United States. The name refers to its long ears. --
Mule pulley (Mach.), an idle pulley for guiding a belt which transmits motion between shafts that are not parallel. --
Mule twist, cotton yarn in cops, as spun on a mule; -- in distinction from yarn spun on a throstle frame. [ 1913 Webster ]