Mule

Mule (pronounced myule)

(1) The sterile offspring of a female horse and a male donkey; a generalised term for any hybrid between the donkey and the horse.

(2) In informal use, a very stubborn person.

(3) In botany, any sterile hybrid.

(4) As drug mule, slang for a person paid to carry or transport contraband, especially drugs, for a smuggler.

(5) 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.

(6) As spinning mule, a machine for spinning cotton or other fibers into yarn and winding the yarn on spindles.

(7) A style of open-backed women’s shoe, historically a lounging slipper that covers the toes and instep or only the instep.

(8) In nautical use, a large triangular staysail set between two masts and having its clew set well aft.

(9) In numismatics, a hybrid coin having the obverse of one issue and the reverse of the succeeding issue, or vice versa.

(10) A cocktail in various flavors (Jamaican Mule, Kentucky Mule & Moscow Mule) based respectively on Rum, Bourbon whiskey and Vodka

(11) As mule-deer, a species native to the western United States and so-named because of its large ears.

Pre 1000: From the Middle English mule, from the Anglo-Norman mule and the Old English mūl, both from the Latin mūlus, from the primitive Indo-European mukslós.   Related were the Middle Dutch mūle, the Old French mul (mule, hinny), the Late Latin muscellus (young he-mule), the Old East Slavic мъшкъ (mŭškŭ) (mule), the Phocian Ancient Greek  μυχλός (mukhlós) (he-ass) and the German Maul, Maultier & Maulesel, again derived from Latin.  It’s thought the Latin word was influenced by the Proto-Italic musklo- which is probably (along with the Ancient Greek myklos (pack-mule) and the Albanian mushk (mule)) a loan-word from one of the languages of Asia Minor.  The noun muleteer (mule driver) dates from the 1530s and was from the French muletier, from mulet (mule), a diminutive formation which in French displaced the Old French mul as the word for "mule".  The adjective mulish (possessing the characteristics imputed to the mule) is used of people thought obstinate rather than hard working; the word was in use by 1751 and the  alternative is mulelike (or mule-like), mulesque apparently either never created or not catching on. Mule is a noun & verb, mulishness & muleteer are nouns, mulishly is an adverb and mulish & mulelike are adjectives; the noun plural is mules. 

The mule became a popular pack animal because it was aid to "combine the strength of the horse with the endurance and surefootedness of the ass" and for centuries mules extensively have been bred to select for one characteristic or the other, those working mountainous trails a different beast from those on the plains.  To be zoologically correct, a mule is properly the offspring of a he-ass and a mare; that of a she-ass and a stallion is technically a hinny while a mule born of a horse and a she-ass is a burdon, a late fourteenth century creation based on the Latin burdonem.  Ordinarily, male mules incapable of procreation and commonly the word is applied allusively of hybrids and things of mixed nature.  The phrase "test mule" entered engineering (and later product development generally) in the 1920s to describe devices built for purposes of evaluation and thus expendable, a fate suffered no doubt by many an unfortunate. 

The mule's well-deserved reputation as a stellar beast of burden appears in the odd idiomatic form but it's the other traits which accounts for most popular use and perhaps surprisingly, given "stubborn as a mule" now appears in much greater frequency than "dumb as a mule" .  The meaning “stupid person” was noted by the 1470s, that of someone "obstinate or stubborn” not emerging until the eighteenth century although the latter use has endured and "working like a mule" proved an acceptable replacement when "working like an N-word" became proscribed.  There must have been some grounds for the beast picking up its reputation for obstinacy but there seems no evidence of the origin of that but it must sufficiently have been recognized to gain currency and become a proverbial descriptor of stubbornness.  A soul with such a tendency said to be "mulish"; within the family, Winston Churchill's (1875-1965; UK prime-minister 1940-1945 & 1951-1955) daughter Sarah (1914-1982) was nicknamed “the mule” (the English upper classes do like nick-names).  It seems likely the phrase "kick like a mule" was born of bitter experience although modern use is almost exclusively figurative, stronger forms of alcoholic drink commonly attracting the label.  It was formalized as the "Moscow Mule" (a cocktail made with vodka, ginger beer, and lime juice) although in the Western intelligence community that term was used also of traitors in the pay of the Soviet Union.  That use was probably modelled on "drug mule", underworld slang for "a smuggler of narcotics" which was noted as early as 1935 and came into general use in the post-war years.  The mule-deer of the western United States picked up the name because of its strikingly large ears.  

The so-named spinning machine dates from 1793 (first known as the "mule jenny" in 1788), the name derived from it being a "hybrid" of Richard Arkwright's (1732–1792) drawing-rollers and the spinning jenny invented by the English carpenter James Hargreaves (circa 1720–1778).  In what seems to have been an imaginative flight of etymological fancy, it was in the eighteenth century suggested the name "mule" was applied because the thing without complaint did so much of the labor which would otherwise have to be undertaken by human hand but there seems no doubt the inspiration was the machine's hybrid origin.  The use to describe the loose slipper worn as footwear was drawn into English in the 1560s from the Old French mule (slipper) from the Latin mulleus calceus (literally “red high-soled shoe”), a shoe worn by Roman patricians and associated with magistrates.  This footwear is unrelated to the long tradition of the Roman Catholic Pope wearing red shoes, the association tracing back to the notion of the blood of Christ falling on his feet as he carried on his back the cross on which he was crucified on Golgotha.  They were made again famous by fashion icon Benedict XVI (1927–2022; pope 2005-2013, pope emeritus 2013-2022) although his successor, Francis (b 1936; pope since 2013), favours plain black.

The mule the clog and the slide

Lindsay Lohan in Alexander Wang Amelia mules, Mykonos, June 2019.  Note the low heel, an example of how the term “mule" is used now by manufacturers to describe just about anything with some degree of openness in the heel.

Mules, by definition are backless but may be sling-backs and can have open or closed toes.  There are many who would classify these as sandals and some manufacturers agree.  In this context "mule" was from the Ancient Roman mulleus calceus a red (or reddish-purple) shoe popular with upper-class Romans and worn as a symbol of office by the three highest magistrates although the scant historical evidence does suggest the Roman footwear looked more like modern clogs than mules and logically, one would expect footwear with thicker, tougher soles would at the time have been preferred for use outdoors.  High-heeled mules became a popular indoor style during the 1700s, influenced by the pattern, a backless overshoe of the sixteenth century, although, by early in the twentieth, mules were often derided as the "dress-wear" of the "better class of prostitutes" and it wasn’t until Marilyn Monroe (1926–1962) adopted the mule in the 1950s they again assumed some respectability.  By the 1990s, mules were among the most popular of shoes.

Chanel Mesh & Grosgrain Mule in black with 3.3 inch (85mm) heel @ US$800, Chanel part-number: G37505 Y55290 94305.

The descriptors mules, clogs and slides are sometimes used interchangeably.  The typical clog is a closed-toed wooden (or other) soled shoe with a heel no more than a couple of inches high.  Clogs are backless (although there are clog boots).  Mules, by comparison, traditionally had a higher heel although the strictness applied to that definition has weakened the emphasis seemingly now on the backlessness although there standards too are loose, slingback mules common.  The term slide derives from being applied to designs permitting the foot to slide in and may thus apply to both mules and clogs rather than being a distinct style.