From apo (away) + kalyptō (to cover) — literally 'an uncovering,' the removal of a veil. Apokalypsis is the disclosure of what was previously hidden, especially divine truth that humans could not discover on their own. It names the final book of the Bible: the Revelation (Apocalypse) of Jesus Christ.
Christianity claims to be a revealed religion — not a human philosophy but a divine apokalypsis. Paul received the gospel 'by revelation of Jesus Christ' (Galatians 1:12), not human teaching. The final apokalypsis is Christ's return: the veil over all reality will be lifted and every eye will see Him. The word implies that truth exists but is hidden until God chooses to unveil it.