menstrual cycle vs tide

menstrual cycle

noun
  • The recurring cycle of physiological changes in the uninseminated females of some animal species that is associated with reproductive fertility; especially the cycle in a human woman. 

tide

noun
  • The periodic change of the sea level, particularly when caused by the gravitational influence of the sun and the moon. 

  • Tendency or direction of causes, influences, or events; course; current. 

  • The period of twelve hours. 

  • Something which changes like the tides of the sea. 

  • A stream, current or flood. 

verb
  • To pour a tide or flood. 

  • To cause to float with the tide; to drive or carry with the tide or stream. 

  • To work into or out of a river or harbor by drifting with the tide and anchoring when it becomes adverse. 

How often have the words menstrual cycle and tide occurred in a corpus of books? (source: Google Ngram Viewer )