From apokalupto; disclosure -- appearing, coming, lighten, manifestation, be revealed, revelation.
see GREEK apokalupto
1. properly, a laying bare, making naked (1 Samuel 20:30).
2. tropically, in N. T. and ecclesiastical language (see end), a. a disclosure of truth, instruction, concerning divine things before unknown — especially those relating to the Christian salvation — given to the soul by God himself, or by the ascended Christ, especially through the operation of the Holy Spirit (1 Corinthians 2:10), and so to be distinguished from other methods of instruction; hence, κατά ἀποκάλυψιν γνωρίζεσθαι, Ephesians 3:3. πνεῦμα ἀποκαλύψεως, a spirit received from God disclosing what and how great are the benefits of salvation, Ephesians 1:17, cf. Ephesians 1:18. with the genitive of the object, τοῦ μυστηρίου, Romans 16:25. with the genitive of the subjunctive, κυρίου, Ἰησοῦ Χριστοῦ, 2 Corinthians 12:1 (revelations by ecstasies and visions, (so 2 Corinthians 12:7)); Galatians 1:12; Revelation 1:1 (revelation of future things relating to the consummation of the divine kingdom); κατ' ἀποκάλυψιν, Galatians 2:2; λαλήσω ... ἐν ἀποκαλύψει, to speak on the ground of (others, in the form of) a revelation, agreeably to a revelation received, 1 Corinthians 14:6; equivalent to ἀποκεκαλυμμενον, in the phrase ἀποκάλυψιν ἔχειν, 1 Corinthians 14:26.
b. equivalent to τό ἀποκαλύπτεσθαι as used of events by which things or states or persons hitherto withdrawn from view are made visible to all, manifestation, appearance, cf. ἀποκαλύπτω, 2, d. and e.: φῶς εἰς ἀποκάλυψιν ἐθνῶν, a light to appear to the Gentiles (others render 'a light for a revelation (of divine truth) to the Gentiles,' and so refer the use to a. above), Luke 2:32; ἀποκαλύψεως δικαιοκρισίας Θεοῦ, Romans 2:5; τῶν υἱῶν τοῦ Θεοῦ, the event in which it will appear who and what the sons of God are, by the glory received from God at the last day, Romans 8:19; τῆς δόξης τοῦ Χριστοῦ, of the glory clothed with which he will return from heaven, 1 Peter 4:13; of this return itself the phrase is used, ἀποκαλύψει τοῦ κυρίου Ἰησοῦ: 2 Thessalonians 1:7; 1 Corinthians 1:7; 1 Peter 1:7, 13. (Among Greek writings, Plutarch uses the word once, Cat. maj. c. 20, of the denudation of the body (also in Paul. Aemil. 14 α. ὑδάτων; in Quomodo adul. ab amic. 32 α. ἁμαρτίας; cf. Sir. 11:27 Sir. 22:22 etc. See Trench, § xciv. and references under the word ἀποκαλύπτω, at the end).)