bivouac

noun

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

   “Townsend hare inhabit this area, particularly above the cabin, and a skier is likely to have one explode from a tree well and disappear into the whiteness as he skis by. Life is a constant bivouac for them -- they spend days huddled in tree wells during storms -- but I suspect they are as content and warm in their luxurious coats as we are in a cabin.”

2. Any temporary encampment.
3. A temporary shelter constructed generally for a few nights.

   “Behold the Mansion reared by Dædal Jack! See the Malt stored in many a plethoric sack, In the proud cirque of Juan's bivouac!”

   “The outing begins by Thursday noon, when the recreational vehicles start rumbling into town and their owners set up bivouacs.”

4. (dated)The watch of a whole army by night, when in danger of surprise or attack.
5. A structure formed by migratory ants out of their own bodies to protect the queen and larvae.

verb

1. (intransitive, transitive)To set up camp.

   “We'll bivouac here tonight.”

   “They reached the fir wood which had caused them so much trouble while it was still daylight, and bivouacked in a hollow just above it. It was tedious gathering the fire wood; […]”

2. (intransitive)To watch at night or be on guard, as a whole army.
3. (intransitive)To encamp for the night without tents or covering.