Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
1. ēr, ēris, m. [χήρ], a hedgehog, Nemes. Cyneg. 57.
Ĕris, ĭdos, f., = Ἔρις, the goddess of strife, Hyg. F. 92.