bullwhip vs flagellum

bullwhip

noun
  • A whip made from plaited leather, often with a knotted end, for use with livestock. 

verb
  • To beat with a bullwhip. 

flagellum

noun
  • A whip 

  • In protists, a long, whiplike membrane-enclosed organelle used for locomotion or feeding. 

  • In bacteria, a long, whiplike proteinaceous appendage, used for locomotion. 

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