reaper vs rider

reaper

noun
  • One who reaps; a person employed to harvest crops from the fields by reaping. 

  • The recluse spider (Loxosceles and Sicarius spp.). 

  • A machine used to harvest crops. 

rider

noun
  • Someone who rides a horse or (later) a bicycle, motorcycle etc. 

  • An amendment or addition to an entertainer's performance contract, often covering a performer's equipment or food, drinks, and general comfort requirements. 

  • A small, sliding piece of thin metal on a balance, used to determine small weights. 

  • Someone riding in a vehicle; a passenger on public transport. 

  • A supplementary question, now especially in mathematics. 

  • An interior rib occasionally fixed in a ship's hold, reaching from the keelson to the beams of the lower deck, to strengthen the frame. 

  • The first Lenormand card, also known as either the horseman or the cavalier. 

  • The second tier of casks in a vessel's hold. 

  • A supplementary clause added to a document after drafting, especially to a bill under the consideration of a legislature. 

  • An old Dutch gold coin with the figure of a man on horseback stamped upon it. 

  • A knight, or other mounted warrior. 

  • An additional matter or question arising in corollary; a qualification. 

  • A piece, such as the rook or bishop, which moves any distance in one direction, as long as no other piece is in the way. 

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