cooker vs steam generator

cooker

noun
  • A device for heating food, a stove. 

  • A person who is cooked; a crazy person. 

  • A person who makes or uses illicit drugs, especially methamphetamine or cannabis. 

  • An appliance or utensil for cooking food. 

  • A cooking apple. 

steam generator

noun
  • a type of boiler fitted in a diesel locomotive or another rail vehicle, which provided steam heating in steam-heated passenger trains that had previously been hauled by steam locomotives. 

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