Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
tentōrĭum, ii, n. [tendo; prop. something stretched out], a tent (syn. tabernaculum), Hirt. B. G. 8, 5; Suet. Aug. 96; id. Tib. 18 med.; Verg. A. 1, 469; Ov. F. 3, 527; id. M. 8, 43; 13, 249; Luc. 1, 396; 6, 270; 9, 912.
* tentōrĭus, a, um, adj. [tentorium], of or for tents: pelles, tent-skins, Val. ap. Treb. Claud. 14.