revelation
n. C / Un. a surprising fact that people did not know before. It can also be the moment you suddenly understand something very important.
n. the disclosure of information that was previously secret or unknown; a surprising and previously unknown fact that is made public.
The news was a shocking revelation to everyone.
The journalist's latest article provided a startling revelation about how the company had been spending its tax breaks.
For many readers, the biography served as a profound revelation, stripping away the subject's public persona to reveal a deeply conflicted and private individual.
Proprialization from revelation. The translation decisions, from the original Greek to the conventional English choices Revelation and Apocalypse, are covered by Wikipedia at Book of Revelation § Title, authorship, and date.
Often used with the preposition 'of' to describe the content being revealed, or 'to' to describe the recipient.