Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Phacus, i, m., = Φάκος, a fortified place near Pella in Macedonia, where the treasury of the Macedonian kings was kept, Liv. 44, 6, 2: Arx Phacus, id. 44, 46, 6.