Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Sēlymbrĭa, ae, f., = Σηλυμβρία, a town of Thrace, on the Propontis, Liv. 33, 39; Mel. 2, 3; Plin. 4, 11, 18, § 47.