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. [ 1913 Webster ]
v. i. [ imp. & p. p. Bivouacked (&unr_;); 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. [ 1913 Webster ]