Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† scalmus, i, m., = σκαλμός, a peg to which an oar was strapped; a thole, tholepin, Vitr. 10, 8 med.; Cic. Brut. 53, 197; id. de Or. 1, 38, 174; Vell. 2, 43, 1: venit (Canius) mature: scalmum nullum videt, not even a thole-pin, i. e. no trace of a boat, Cic. Off. 3, 14, 59.