Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† eclīpsis, is, f., = ἔκλειψις (a forsaking, being absent): solis, an eclipse of the sun, Auct. Her. 3, 22, 36: lunae, Hyg. Astr. 4, 14; and without gen., Plin. 2, 12, 9, § 53 (pure Lat. defectio and defectus).