A revelation is the act of revealing something that was hidden or unknown, or the surprising information itself. When a detective has a sudden revelation about who committed a crime, they suddenly understand something they couldn't figure out before. When a friend shares a personal revelation with you, they're telling you something important about themselves that you didn't know.

The word carries a sense of surprise or significance. Finding out your teacher likes pizza isn't a revelation, but discovering that she once competed in the Olympics would be. A revelation changes how you understand something or someone.

In religious contexts, revelation means divine truth that God reveals to people. The Book of Revelation is the last book of the Christian Bible and describes visions of the end times. When people capitalize the word in this context, they're usually referring to this specific biblical book.

Scientists experience revelations too. When Marie Curie realized that radioactivity came from inside atoms themselves, it was a revelation that transformed physics. The word suggests that moment when something hidden becomes clear, when a mystery suddenly makes sense, or when you see something familiar in a completely new way.