What is the meaning of fact?

noun

• A piece of information about circumstances that exist or events that have occurred.
  • usage: "first you must collect all the facts of the case"
• A statement or assertion of verified information about something that is the case or has happened.
  • usage: "he supported his argument with an impressive array of facts"
• An event known to have happened or something known to have existed.
  • usage: "your fears have no basis in fact"; "how much of the story is fact and how much fiction is hard to tell"
• A concept whose truth can be proved.
  • usage: "scientific hypotheses are not facts"