"to split, part or divide by force," Old English cleofan, cleven, cliven "to split, separate" (class II strong verb, past tense cleaf, past participle clofen), from Proto-Germanic *kleuban (source also of Old Saxon klioban, Old Norse kljufa, Danish klöve, Dutch kloven, Old High German klioban, German klieben "to cleave, split"), from PIE root *gleubh- "to tear apart, cleave."
Past tense form clave is recorded in Northern writers from 14c. and was used with both verbs (see cleave (v.2)), apparently by analogy with other Middle English strong verbs. Clave was common to c. 1600 and still alive at the time of the KJV; weak past tense cleaved for this verb also emerged in 14c.; cleft is still later. The past participle cloven survives, though mostly in compounds.
"to adhere, cling," Middle English cleven, clevien, cliven, from Old English clifian, cleofian "to stick fast, adhere," also figurative, from West Germanic *klibajan (source also of Old Saxon klibon, Old High German kliban, Dutch kleven, Old High German kleben, German kleben "to stick, cling, adhere"), from PIE *gloi- "to stick" (see clay).
The confusion was less in Old English when cleave (v.1) was a class 2 strong verb; but it has grown since cleave (v.1) weakened, which may be why both are largely superseded by stick (v.) and split (v.).
"split, cloven," late 14c., past-participle adjective from cleave (v.1)). Cleft palate attested from 1828.
"divided, split," Old English clofen, past-participle adjective from cleave (v.1). Sometimes shortened to clove, hence clove-hitch (1769), etc. Cloven hoof, characteristic of ruminant quadrupeds (and ascribed in mythology to Pan and the Devil) is from c. 1200.
1570s, alteration (by influence of cleft, new weak past participle of cleave (v.1)), of Middle English clift "fissure, rift, space or opening made by cleaving" (early 14c.), from Old English geclyft (adj.) "split, cloven," from Proto-Germanic *kluftis (compare Old High German chluft, German Kluft, Danish kløft "cleft, fissure, gap"), from PIE root *gleubh- "to tear apart, cleave." In Middle English anatomy, it meant "the parting of the thighs" (early 14c.).
1805, in geology and mineralogy, "tendency (of rocks or gems) to break cleanly along natural fissures," from cleave (v.1) + -age. General meaning "action or state of cleaving or being cleft" is from 1867.
The sense of "cleft between a woman's breasts in low-cut clothing" is first recorded 1946, defined in a "Time" magazine article [Aug. 5] as the "Johnston Office trade term for the shadowed depression dividing an actress' bosom into two distinct sections;" traditionally first used in this sense by U.S. publicist Joseph I. Breen (1888-1965), head of the Production Code Administration (replaced 1945 by Eric Johnston), enforcers of Hollywood self-censorship, in reference to Jane Russell's costumes and poses in "The Outlaw."
Proto-Indo-European root meaning "to tear apart, cleave."
It is the hypothetical source of/evidence for its existence is provided by: Greek glyphe "a carving," glyphein "to hollow out, cut out with a knife, engrave, carve;" Latin glubere "to peel, shell, strip;" Old High German klioban, Old English cleofan, Old Norse kljufa "to cleave," Old Norse klofi, Middle Dutch clove "a cleft."
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]