hasp vs holdback

hasp

noun
  • A clasp, especially a metal strap fastened by a padlock or a pin; also, a hook for fastening a door. 

  • A spindle to wind yarn, thread, or silk on. 

  • An instrument for cutting the surface of grassland; a scarifier. 

verb
  • To shut or fasten with a hasp. 

holdback

noun
  • The strap or part of the harness so used. 

  • The projection or loop, on the thill of a vehicle, to which a strap of the harness is attached, to hold back a carriage when going downhill, or in backing. 

  • restraint (act or result of holding back, device that restrains) 

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