Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Ăvĭēnus, i, m.: Rufus Festus Avienus, a Roman poet in the last half of the fourth century, whose most distinguished work is a Metaphrasis Periegesos Dionysii, and a metaphrase of the Phœnomena of Aratus; cf. Bähr, Lit. Gesch. pp. 128 sq. and 153; Teuffel. Rom. Lit. § 413.