O.E.
cyssan "to kiss," from P.Gmc.
*kussijanan (cf. O.S.
kussian, O.N.
kyssa, O.Fris.
kessa, Ger.
küssen), from
*kuss-, probably ultimately imitative of the sound. The O.E. noun was
coss, which became M.E.
cuss, but this yielded to
kiss, from the verb. For vowel evolution, see
bury. There appears to be no common I.E. root word for "kiss," though suggestions of a common
ku- sound may be found in the Gmc. root and Gk.
kynein "to kiss," Hittite
kuwash-anzi "they kiss," Skt.
cumbati "he kisses."
"Kissing, as an expression of affection or love, is unknown among many races, and in the history of mankind seems to be a late substitute for the more primitive rubbing of noses, sniffing, and licking." [Buck, p.1113]
Some languages make a distinction between the kiss of affection and that of erotic love (cf. L.
saviari "erotic kiss," vs.
osculum, lit. "little mouth"). Fr.
embrasser "kiss," but lit. "embrace," came about in 17c. when the older word
baiser (from L.
basiare) acquired an obscene connotation.
Kiss of death (1948) is in ref. to Judas' kiss in Gethsemane (Matt. xxvi.48-50). Slang
kisser "mouth" is from 1860. Insulting invitation
kiss my ass is at least from 1705, but probably much older (cf. "The Miller's Tale").
[kis] 
