Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
dē-tendo, no perf., sum, 3, v. a., to unstretch, relax a thing strained (very rare): tabernacula, to strike the tents, * Caes. B. C. 3, 85, 3; Liv. 41, 3, 1.