Lewis & Short

Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.

Ărĕlas, ātis (Ărĕlātē, ēs, Suet. Tib. 4; Aus. Clar. Urb. 8), f., = Ἀρέλαται or Ἀρέλατον, a town in Southern Gaul, on the eastern branch of the Rhone, now Arles, Caes. B. C. 1, 36; cf. Mann. Gall. 96.
Hence, Ărĕlātensis, e, adj., Arelatian: ager, Plin. 10, 42, 57, § 116; plur., Ărĕlāten-ses, ium, m., the inhabitants of Arelas, Dig. 32, 2, 34.