bathing beauty or (old) bathing belle noun

An attractive woman in a swimsuit, esp when competing in a beauty contest

bathing box or bathing hut noun

A small structure for bathers to change in

bathing cap noun

A tight rubber cap worn on the head to keep the hair dry and out of the way when swimming

bathing costume or bathing dress noun (old)

A swimsuit

bathing machine noun (historical)

A wheeled bathing hut for transporting a bather into the sea

bathing suit noun (old or N American)

A swimsuit