ebb vs open sea

ebb

noun
  • The receding movement of the tide. 

  • A European bunting, the corn bunting (Emberiza calandra, syns. Emberiza miliaria, Milaria calandra). 

  • A gradual decline. 

  • A low state; a state of depression. 

verb
  • to fish with stakes and nets that serve to prevent the fish from getting back into the sea with the ebb 

  • To cause to flow back. 

  • to flow back or recede 

  • to fall away or decline 

adj
  • low, shallow 

open sea

noun
  • That part of the sea out of sight of land. 

  • A sea open to all nations, i.e. not a mare clausum. 

How often have the words ebb and open sea occurred in a corpus of books? (source: Google Ngram Viewer )