bivouac
/ˈbɪvuæk; `bɪvʊˌæk/ n
temporary camp without tents or any other cover, esp used by soldiers or mountaineers （无帐篷或其他遮盖物的）临时营地（尤指 士兵或登山者所用的）. bivouac, v [I]
(-ck-) make or camp in a bivouac 在露天地上宿营
We bivouacked on the open plain. 我们在开阔的原野上露营.