bivouac (n.)

1702, "encampment of soldiers that stays up on night watch in the open air, dressed and armed," from French bivouac (17c.), said to be a word from the Thirty Years' War, ultimately from Swiss/Alsatian biwacht "night guard," from bei- (from Old High German bi- "by," here perhaps as an intensive prefix; see by) + wacht "guard" (from Proto-Germanic *wahtwo, from PIE root *weg- "to be strong, be lively"). Sense of "outdoor camp" is from 1853. According to OED not a common word in English before the Napoleonic Wars. Italian bivacco is from French. As a verb, 1809, "to post troops in the night;" meaning "camp out-of-doors without tents" is from 1814.

updated on June 10, 2017

Definitions of bivouac from WordNet
bivouac (n.)
temporary living quarters specially built by the army for soldiers;
Synonyms: camp / encampment / cantonment
bivouac (n.)
a site where people on holiday can pitch a tent;
Synonyms: campsite / campground / camping site / camping ground / encampment / camping area
bivouac (v.)
live in or as if in a tent;
Synonyms: camp / encamp / camp out / tent
Etymologies are not definitions. From, not affiliated with etymonline.