Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Ŭlū̆brae, ārum, f., a small town of Latium, by the Pontine Marshes, now Cisterna, Cic. Fam. 7, 18, 3; Hor. Ep. 1, 11, 30; Juv. 10, 102; Inscr. Orell. 121 sq.
Hence,