Apocalypse, n.
Etymology: [L. apocalypsis, Gr. apocalypse.]
1. The revelation delivered to St. John, in the isle of Patmos, near the close of the first century, forming the last book of the New Testament.
2. Anything viewed as a revelation; as disclosure. The new apocalypse of Nature. Carlyle.
Shades of meaning
Fernald has no entry of its own for apocalypse; he lists it under revelation.
Where he writes about it:
Apocalypse (Gr. apo, from, and kalypto, cover), literally an uncovering, comes into English as the name of the closing book of the Bible. — from revelation
The Apocalypse unveils the future, as if to the very gaze of the seer; the whole gospel is a disclosure of the mercy of God; the character of Christ is a manifestation of the divine holiness and love; all Scripture is a revelation of the divine will. — from revelation