Pronunciation: (myOOl),[key] —n. 1. the sterile offspring of a female horse and a male donkey, valued as a work animal, having strong muscles, a body shaped like a horse, and donkeylike long ears, small feet, and sure-footedness. Cf. hinny1.
2. any hybrid between the donkey and the horse.
3. Informal.a very stubborn person.
4. Bot.any sterile hybrid.
5. Slang.a person paid to carry or transport contraband, esp. drugs, for a smuggler.
6. a small locomotive used for pulling rail cars, as in a coal yard or on an industrial site, or for towing, as of ships through canal locks.
7. Also called spinning mule. a machine for spinning cotton or other fibers into yarn and winding the yarn on spindles.
8. Naut.a large triangular staysail set between two masts and having its clew set well aft.
9. Numis.a hybrid coin having the obverse of one issue and the reverse of the succeeding issue, or vice versa.
10. Biol.a hybrid, esp. one between the canary and some other finch.
Pronunciation: (myOOl),[key] —n. a lounging slipper that covers the toes and instep or only the instep.