Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
‡ cartĭbŭlum (-blum), i, n., a kind of oblong table of stone, standing on a pedestal: a gerendo gertibulum, unde cartibulum post dictum, Varr. L. L. 5, § 125 Müll. p. 35 sq. Bip.