Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
nāvĭgĭŏlum, i, n. dim. [navigium], a small vessel, a bark. boat, Lentul. ap. Cic. Fam. 12, 15, 2; Auct. Bell. Al. 63, 2.