Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† ăpŏcălypsis, is, f., = ἀποκάλυψις, a disclosing, revelation (eccl. Lat.): apocalypsim habet, Vulg. 1 Cor. 14, 26: apocalypsis Jesu Christi, ib. Apoc. 1, 1: Joannis, the Revelation, the Apocalypse, Tert. adv. Marc. 4, 5.