Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Nebiodūnum (Noviodūnum), i, n., a city of Lower Mœsia, Cod. Th. 10, 21, 1.
Nŏvĭŏdūnum, i, n., the name of several cities in Gaul.