Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† Aex, = αἴξ (Goat), the name of a rocky island in the Ægean Sea, between Chius and Tenus: Aex nomine a specie caprae, repente e medio mari exsiliens, Plin. 4, 11, 18, § 51.