waterspout vs willy-willy

waterspout

noun
  • A whirlwind that forms over water, not associated with a mesocyclone of a thunderstorm (contrary to a true tornado). 

  • A plume of water rising from the surface of a body of water as the result of an impact or explosion. 

  • A true tornado that passes over a body of water. 

  • A channel through which water is discharged, especially from the gutters of a roof. 

willy-willy

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