bottoms vs fen

bottoms

noun
  • The bottom (trouser) part of clothing, as in pyjama bottoms, tracksuit bottoms. 

fen

noun
  • A type of wetland fed by ground water and runoff, containing peat below the waterline, characteristically alkaline. 

  • A unit of currency in China, one-hundredth of a yuan. 

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