Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† 1. astĕrĭŏn, ii, n., = ἀστέριον, a species of spider, Plin. 29, 4, 27, § 86.
2. Astĕrĭōn, ontis, m., = Ἀστερίων, a river in Argolis, Stat. Th. 4, 122; 4, 714.