Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† pŏlypŏdĭum (-ĭon), ii, n., = πολυπόδιον, a kind of fern, polypody, Plin. 16, 44, 92, § 244; 26, 12, 75, § 122.