late 15c., "one who splits," agent noun from cleave (v.1). Originally "one who splits boards with a wedge instead of sawing;" attested as part of a surname from mid-14c. Meaning "butcher's long-bladed chopper" is from mid-15c. Marrow-bones and cleavers as instruments of "rough music" is from 1716.
This last ["Marrowbones and Cleaver"] is a sign in Fetter Lane, originating from a custom, now rapidly dying away, of the butcher boys serenading newly married couples with these professional instruments. Formerly, the band would consist of four cleavers, each of a different tone, or, if complete, of eight, and by beating their marrowbones skilfully against these, they obtained a sort of music somewhat after the fashion of indifferent bell-ringing. When well performed, however, and heard from a proper distance, it was not altogether unpleasant. ... The butchers of Clare market had the reputation of being the best performers. ... This music was once so common that Tom Killigrew called it the national instrument of England. [Larwood & Hotten, "The History of Signboards from the Earliest Times to the Present Day," London, 1867]
Perhaps it is related to Middle Low German keie "lance, spear" on notion of "tool to cleave with," from Proto-Germanic *ki- "to cleave, split" (cognates: German Keil "wedge," Gothic us-kijans "come forth," said of seed sprouts, keinan "to germinate"). But Liberman writes, "The original meaning of *kaig-jo- was presumably '*pin with a twisted end.' Words with the root *kai- followed by a consonant meaning 'crooked, bent; twisted' are common only in the North Germanic languages." Compare also Sanskrit kuncika- "key," from kunc- "make crooked."
Modern pronunciation is a northern variant predominating from c. 1700; earlier and in Middle English it often was pronounced "kay." Meaning "that which holds together other parts" is from 1520s. Meaning "explanation of a solution" (to a set problem, code, etc.) is from c.1600.
The musical sense originally was "tone, note" (mid-15c.). In music theory, the sense developed 17c. to "sum of the melodic and harmonic relationships in the tones of a scale," also "melodic and harmonic relationships centering on a given tone." Probably this is based on a translation of Latin clavis "key," used by Guido for "lowest tone of a scale," or French clef (see clef; also see keynote). Sense of "mechanism on a musical instrument operated by the player's fingers" is from c. 1500, probably also suggested by uses of clavis. OED says this use "appears to be confined to Eng[lish]." First of organs and pianos, by 1765 of wind instruments; transferred to telegraphy by 1837 and later to typewriters (1876).
"female intercrural foramen," or, as some 18c. writers refer to it, "the monosyllable," Middle English cunte "female genitalia," by early 14c. (in Hendyng's "Proverbs" — ʒeve þi cunte to cunni[n]g, And crave affetir wedding), akin to Old Norse kunta, Old Frisian, Middle Dutch, and Middle Low German kunte, from Proto-Germanic *kunton, which is of uncertain origin. Some suggest a link with Latin cuneus "wedge" (which is of unknown origin), others to PIE root *geu- "hollow place," still others to PIE root *gwen- "woman."
The form is similar to Latin cunnus "female pudenda" (also, vulgarly, "a woman"), which is likewise of disputed origin, perhaps literally "gash, slit" (from PIE *sker- "to cut") or "sheath" (Watkins, from PIE *(s)keu- "to conceal, hide"). De Vaan rejects this, however, and traces it to "a root *kut-meaning 'bag', 'scrotum', and metaphorically also 'female pudenda,' " source also of Greek kysthos "vagina; buttocks; pouch, small bag" (but Beekes suspects this is a Pre-Greek word), Lithuanian kutys "(money) bag," Old High German hodo "testicles."
Hec vulva: a cunt. Hic cunnus: idem est. [from Londesborough Illustrated Nominale, c. 1500, in "Anglo-Saxon and Old English Vocabularies," eds. Wright and Wülcker, vol. 1, 1884]
First known reference in English apparently is in a compound, Oxford street name Gropecuntlane cited from c. 1230 (and attested through late 14c.) in "Place-Names of Oxfordshire" (Gelling & Stenton, 1953), presumably a haunt of prostitutes. Used in medical writing c. 1400, but avoided in public speech since 15c.; considered obscene since 17c.
in Middle English also conte, counte, and sometimes queinte, queynte (for this, see Q). Chaucer used quaint and queynte in "Canterbury Tales" (late 14c.), and Andrew Marvell might be punning on quaint in "To His Coy Mistress" (1650).
"What eyleth yow to grucche thus and grone? Is it for ye wolde haue my queynte allone?" [Wife of Bath's Tale]
Under "MONOSYLLABLE" Farmer lists 552 synonyms from English slang and literature before launching into another 5 pages of them in French, German, Italian, Spanish, and Portuguese. [A sampling: Botany Bay, chum, coffee-shop, cookie, End of the Sentimental Journey, fancy bit, Fumbler's Hall, funniment, goatmilker, heaven, hell, Itching Jenny, jelly-bag, Low Countries, nature's tufted treasure, penwiper, prick-skinner, seminary, tickle-toby, undeniable, wonderful lamp, and aphrodisaical tennis court, and, in a separate listing, Naggie.] Dutch cognate de kont means "a bottom, an arse," but Dutch also has attractive poetic slang ways of expressing this part, such as liefdesgrot, literally "cave of love," and vleesroos "rose of flesh."
Alternative form cunny is attested from c. 1720 but is certainly much earlier and forced a change in the pronunciation of coney (q.v.), but it was good for a pun while coney was still the common word for "rabbit": "A pox upon your Christian cockatrices! They cry, like poulterers' wives, 'No money, no coney.' " [Philip Massinger: "The Virgin-Martyr," Act I, Scene 1, 1622]