barrow vs knoll

barrow

noun
  • A hill. 

  • A castrated boar. 

  • A long sleeveless flannel garment for infants. 

  • A mound of earth and stones raised over a grave or graves. 

  • A small vehicle used to carry a load and pulled or pushed by hand. 

  • A wicker case in which salt is put to drain. 

  • A heap of rubbish, attle, or other such refuse. 

knoll

noun
  • A small mound or rounded hill. 

  • A rounded, underwater hill with a prominence of less than 1,000 metres, which does not breach the water's surface. 

  • A knell. 

verb
  • To ring (a bell) mournfully; to knell. 

  • To sound (something) like a bell; to knell. 

  • To call (someone, to church) by sounding or making a knell (as a bell, a trumpet, etc). 

  • To arrange related objects in parallel or at 90 degree angles. 

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