double boiler vs stove

double boiler

noun
  • A large pan containing hot water, into which other smaller pans are set in order to cook food at low heat (below the boiling point) or to keep food warm. 

  • A pair of interlocking pots, the lower one filled with water which when boiling heats the contents of the upper pot. 

stove

noun
  • A device for heating food, (UK) a cooker. 

  • A hothouse (heated greenhouse). 

  • A heater, a closed apparatus to burn fuel for the warming of a room. 

  • A stovetop, with hotplates. 

verb
  • To keep warm, in a house or room, by artificial heat. 

  • To heat or dry, as in a stove. 

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