Other forms: second sights
If you believe in second sight, it means you think that it's possible for people to see into the future. Someone who claims to have second sight might call themselves a clairvoyant and hover over a crystal ball.
If you saw something that was going to happen in the future, and then it actually occurred, you'd have second sight. It's one form of ESP, or extrasensory perception — the ability to see things that ordinary senses don't show. Second sight seems at first to be an odd name, since it means "the sight of events before they occur," — not afterward. Some believe it comes from the idea that physical sight comes first, and second sight develops later.