Past
The past is something that has already happened. If something has not happened yet, it is called the future.
Professors and researchers that study the events of the past, and try to explain why these events happened are called history professors or historians.
Many books, movies, and television shows tell made-up stories about the past. These are called historical fiction. Some books, movies, and television shows from a style called science fiction or fantasy tell made-up stories about being able to travel through time back to the past.