mule
1 Americannoun
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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.
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any hybrid between the donkey and the horse.
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Informal. a very stubborn person.
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Botany. any sterile hybrid.
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Biology. a hybrid, especially one between the canary and some other finch.
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Slang. a person paid to carry or transport contraband, especially drugs, for a smuggler.
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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.
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Also called spinning mule. a machine for spinning cotton or other fibers into yarn and winding the yarn on spindles.
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Nautical. a large triangular staysail set between two masts and having its clew set well aft.
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Numismatics. a hybrid coin having the obverse of one issue and the reverse of the succeeding issue, or vice versa.
idioms
noun
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a lounging slipper that covers the toes and instep or only the instep.
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a woman's shoe resembling this.
noun
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the sterile offspring of a male donkey and a female horse, used as a beast of burden Compare hinny 1
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any hybrid animal
a mule canary
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Also called: spinning mule. a machine invented by Samuel Crompton that spins cotton into yarn and winds the yarn on spindles
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informal an obstinate or stubborn person
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slang a person who is paid to transport illegal drugs for a dealer
noun
Etymology
Origin of mule1
First recorded before 1000; Middle English, from Old French, from Latin mūla “mule” (feminine); replacing Old English mūl, from Latin mūlus (masculine)
Origin of mule2
First recorded in 1350–1400; Middle English mule, moule “sore spot on the heel, chilblain,” perhaps from Middle Dutch mūle
Explanation
When a donkey and a horse have a baby, it's a mule. A mule, however, can not make babies — since it has an odd number of chromosomes (63, to be exact). While donkeys can be notoriously stubborn and horses can be fragile, mules are sturdy, patient, and live long lives. Mules always have a donkey father and a horse mother, while the opposite combination (a female mule and male horse) is called a hinny, and it's less common. A completely unrelated definition of mule is a slip-on shoe or slipper. This second meaning is from the Latin mulleus calceus, the footwear of Roman patricians, "red high-soled shoe."
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Customers wield big Messi head cutouts, and the bar offers a cocktail dubbed the Messi Mule.
From The Wall Street Journal • Apr. 11, 2026
The train will get you back to Tokyo in time for a nightcap, perhaps at Studio Mule, a listening bar in Shibuya that specializes in natural wine.
From The Wall Street Journal • Jan. 24, 2026
“Muddle them in the bottom of a glass and add soda water. You’ve basically constructed your own Moscow Mule with fresh ingredients that’ll blow you away.”
From Salon • Jan. 18, 2026
To spice up your dry Moscow Mule, try combining ginger beer and lime juice with a non-alcoholic sparkling cider.
From Salon • Jan. 18, 2026
Others in the cafe—Mrs. Clare and Mabel Helm and a husky young farmer who had stopped to buy a plug of Brown’s Mule chewing tobacco—muttered and mumbled.
From "In Cold Blood" by Truman Capote
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Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.