Anyway, the story for the word in its modern English use is that the two-piece bathing suit was introduced in 1946, and in search of a name for it, the designer chose Bikini, in reference to an (inhabited but evacuated) atoll in the Marshall Islands which had just been used for testing the atomic bomb. (The joke was, this bathing suit is as hot as a recently irradiated tropical island - ha ha ha).
It's observable that "kini" has become a cran-morpheme, appearing in forms like monokini (a one piece, or maybe topless form) and tankini (whose top is like a tank top). The brief ADS discussion suggested the backformation [bi+kini] was purposeful. Regardless, Nikolaev was unable to find help regarding the origin of the place name, as his summary several weeks later indicates:
I thank all who got in touch with me and who shared their know-how on the subject. However, no Marshallese connection was established and I still do not know for certain whether the bi- in bikini, by any off chance, came from the Latin bin, bis. While at this point we do not have the Marshallese etymology of the word bikini, I suggest that we do not close the current discussion.
The original query seemed innocent enough, but the sum kind of lets on speculation that the bi portion of the word bikini was always the latinate bi. (I think. Nobody (hopefully) would suggest the Romans made it that far east, or west, so I assume the null hypothesis is that there is a place called Kini to which a creative designer attached bi-.)
When I first saw the post I meant to write to Nikolaev after simply reaching behind me to crack open Abo, Bender, Capelle, and Debrum's Marshallese English Dictionary. But it was not behind me; instead, it was tucked away in the stacks on the 7th floor of Davidson Library. But the other day I was reminded of the issue when browsing the news and finding this story and photo.
So I went to get the dictionary, which I knew has a helpful section just on Marshallese place names. However, Marshallese orthography is opaque. The letter [b] is used, but stands for a velarized labial stop, which other Micronesian spelling systems express with [pw]. Also, the vowels are unusual: symbols like a, e, i, o, and u are all used, but are distributed over a four-height series in which each vowel has 3 (or so) allophones in the backness dimension.
What this means is that in looking for the Marshallese word bikini, you need to cast a wide net, especially since there is no such representation using that exact string of letters. Instead, it seems that the spelling of bikini is probably an English transliteration of a Japanese or German rendition. So I had to check b-words spelled with any vowel.
I scanned through the b-words in the place-name list and regular Marshallese-English section, with little luck. There were some leads, including bokwan [beqan], a recurring place-name formative, būkien [bikiyen] "its cape", būkōn [biken] "cape", bukun [biqin] "grove", and bok [beq] "sand" -- nothing quite close enough.
Frustrated, I wondered if the transliteration is actually a p-initial word. That is, perhaps the place name actually begins with a non-velarized labial stop, which Marshallese spells [p]. Then I found a place name Pikinni [pikinniy], which evidently is composed of pik "surface" and ni "coconut". It's listed in the place-name section of Abo et al, but it's not clear there whether the word applies specifically to the Bikini atoll.
I found confirmation, though, by looking up some official resources on the Marshall Islands. First I found their US Embassy, which links to a visitor's site, which links to an online library, with this entry on the Bikini atoll. In short, its name in Marshallese really is Pikinni. The probable trajectory is that the real place name was transliterated as Bikini, whose spelling precipitated the backformational removal of bi-.
(via Language Hat)