ETYM French bivouac, bivac, prab. from German beiwache, or beiwacht; bei by, near + wachen to watch, wache watch, guard. Related to By, and Watch.
1. The watch of a whole army by night, when in danger of surprise or attack.
2. An encampment for the night without tents or covering.
1. To watch at night or be on guard, as a whole army.
2. To encamp for the night without tents or covering.