Word Origin & History
1948, from Fr. coinage, 1947, named for U.S. A-bomb test of June 1946 on Bikini, Marshall Islands atoll, locally Pikinni and said to derive from pik "surface" and ni "coconut," but this is uncertain. Various explanations for the swimsuit name have been suggested, none convincingly, the best being an
analogy of the explosive force of the bomb and the impact of the bathing suit style on men's libidos (cf. c.1900 British slang assassin "an ornamental bow worn on the female breast," so called because it was very "killing").
"Bikini, ce mot cinglant comme l'explosion même ... correspondant au niveau du vêtement de plage à on anéantissement de la surface vêtue; à une minimisation extrême de la pudeur." [Le Monde, 1947]
Variant style trikini (1967), with separate bra cups held on by Velcro, falsely presumes a compound in bi-.