tidal wave vs tsunami

tidal wave

noun
  • A sudden and powerful surge. 

  • A large, sudden, and disastrous wave of water caused by a tremendous disturbance in the ocean; a tsunami. (See Usage notes below.) 

  • A crest of ocean water resulting from tidal forces. 

  • A large, sudden inundation of water from the storm surge, or waves of that surge; a sudden surge of river water. 

  • A large and sudden rise and fall in the tide. 

tsunami

noun
  • A large and generally unstoppable surge. 

  • A very large and destructive wave, generally caused by a tremendous disturbance in the ocean, such as an undersea earthquake or volcanic eruption. Tsunami are usually a series of waves, or wave train. 

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