Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† astrŏnŏmĭcus, a, um, adj., = ἀστρονομικός, astronomical: Astrŏnŏmĭca, ōrum, n., the tille of an unfinished poem by Manilius, and of a treatise by Hyginus.