bivi vs bivouac

bivi

noun
  • A bivouac, a temporary camp. 

bivouac

noun
  • Any temporary encampment. 

  • An encampment for the night, usually without tents or covering. 

  • A temporary shelter constructed generally for a few nights. 

  • A structure formed by migratory ants out of their own bodies to protect the queen and larvae. 

verb
  • To encamp for the night without tents or covering. 

  • To set up camp. 

  • To watch at night or be on guard, as a whole army. 

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