bathing suits, swimming trunks, bikinis. 泳衣, 男式泳褲, 比基尼

Bathing suits morphed into the bikinis and trunks. 

泳衣演變成的比基尼和泳褲

This group of girlfriends running out of the cold October sea in 1925 are sporting the now-sleeveless bathing suits popular with the time

Incredible photographs of New York beaches from 1880 to 1940s | Daily Mail Online
Read more: http://www.dailymail.co.uk/news/article-3149821/Incredible-photographs-New-York-beaches-1880-1940s.html#ixzz3f0gQoeWt
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Trunks (clothing) - Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Trunks_(clothing)
swimming trunks是什么意思? swimming trunks翻译(中文英文):泳裤…《抓鸟》英语词典
n. 泳褲
http://dict.zhuaniao.com/en/swimming+trunks/