古英語のcyssan「接吻する」から。原語ゲルマン語の*kuss「接吻する音」に由来する。osculateと比較。
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 (compare Latin saviari "erotic kiss," vs. osculum, literally "little mouth"). French embrasser "kiss," but literally "embrace," came about in 17c. when the older word baiser (from Latin basiare) acquired an obscene connotation. Insulting invitation kiss my ass is at least from 1705, but probably much older (see "The Miller's Tale").