hassock vs pillion

hassock

noun
  • A thick cushion used as a seat; an ottoman or pouffe. 

  • A cushion used primarily in churches for kneeling on while praying. 

  • A dense clump of grass or vegetation; a tussock. 

pillion

noun
  • The cushion of a saddle. 

  • The person riding in the pillion. 

  • A similar second saddle on a motorcycle for a passenger. 

  • A pad behind the saddle of a horse for a second rider. 

adv
  • Riding behind the driving rider, as when positioned on the rump of a mount. 

verb
  • To ride on a pillion. 

  • To put a pillion on a horse. 

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