Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Aegĭmŭrus, i, f., = Αἰγίμορος, an island situated over against Carthage, now Zowamour or Zimbra, Plin. 5, 7, 7, § 42; Liv. 30, 24, 9; Auct. B. Afr. 44; Flor. 2, 2, 30.