lanugo vs seta

lanugo

noun
  • Soft down or fine hair, specifically that covering the human foetus or a tumorous area. 

seta

noun
  • A bristle or hair 

  • The stalk of a moss sporangium, or occasionally in a liverwort. 

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