headsail vs topsail

headsail

noun
  • Any sail (of a sailing vessel) set forward of the foremost mast. 

topsail

noun
  • In a fore-and-aft-rigged sailing boat, the sail that is set above the gaff at the top part of the mast. 

  • A sail or either of the two sails rigged just above the course sail and supported by the topmast on a square-rigged sailing ship. 

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