Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
1. Aesis, is, m., a river in Umbria, Plin. 11, 42, 97, § 241.
2. Aesis, is, f., a town in Umbria on the river Æsis: COL. AESIS, Inscr. Orell. 3899.
Whence,