bikini vs swimsuit

bikini

noun
  • A brief two-piece bathing suit worn by girls and women, especially one that exposes the midriff and navel. 

  • A brief bathing suit worn by men. 

swimsuit

noun
  • A garment worn for swimming. 

  • A tight-fitting one-piece garment worn by women and girls. 

How often have the words bikini and swimsuit occurred in a corpus of books? (source: Google Ngram Viewer )