An apocalypse (Ancient Greek: ἀποκάλυψις apocálypsis, from ἀπό and καλύπτω meaning 'un-covering'), translated literally from Greek refers to a revelation of something hidden, although this sense did not enter English until the 14th century.^[1] In religious contexts it is usually a revelation of hidden meaning - hidden from human knowledge in an era dominated by falsehood and misconception. In theRevelation of John (Greek Ἀποκάλυψις Ἰωάννου, Apocalypsis Ioannou), the last book of the New Testament, the revelation which John receives is that of the ultimate victory of good over evil and the end of the present age, and that is the primary meaning of the term, one that dates to 1175.^[2] Today, it is commonly used in reference to any prophetic revelation or so-called End Time scenario, or to the end of the world in general.

from: Wikipedia