Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
con-tigno, no perf., ātum, 1, v. a. [tignum], to join together with beams, to furnish with beams, joists, or rafters (rare), Caes. B. C. 2, 15; Vitr. 1, 5; Plin. 9, 3, 2, § 7.