Biv"ouac (&?;), n. [F. bivouac, bivac, prab. fr. G. beiwache, or beiwacht; bei by, near + wachen to watch, wache watch, guard. See By, and Watch.] (Mil.) (a) The watch of a whole army by night, when in danger of surprise or attack. (b) An encampment for the night without tents or covering.

Biv"ouac, v. i. [imp. & p. p. Bivouacked (&?;); p. pr. & vb. n. Bivouacking.] (Mil.) (a) To watch at night or be on guard, as a whole army. (b) To encamp for the night without tents or covering.

• The watch of a whole army by night, when in danger of surprise or attack.
  
• An encampment for the night, usually without tents or covering.
  
• A temporary encampment.
       quotations:
       *"The outing begins by Thursday noon, when the recreational vehicles start rumbling into town and their owners set up bivouacs." —Boston Globe, September 23, 2005