The bikini swimsuit was named after the Bikini Atoll. A bit of a mixup from OP though: it wasn’t named after fusion bombs. The bikini swimsuit was announced a few days after the first public fission bomb test there (Crossroads Able) in 1946. The first fusion bomb test there (Castle Bravo) wasn’t until 1954.
Besides, what's the bathing suit name reference ? I don't get it.