lamppost vs signal fire

lamppost

noun
  • The pole that holds up a light so it can illuminate a wide area, such as holds up a streetlight. 

  • A tall, thin person. 

signal fire

noun
  • A fire lit to convey a message or serve as a beacon, by either light or smoke. 

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