A form of double attack where one piece threatens two enemy pieces at the same time. In a triple fork, three enemy pieces are threatened.

A double attack, usually by a Knight or Pawn (thus looking like a “fork” in the road), a common chess tactic.

A simultaneous attack by a single piece on two (or more) of the opponent's pieces (or other direct target, such as a mate threat). When the attacker is a knight the tactic is often specifically called a knight fork. Some sources state that only a knight can give a fork and that the term double attack is correct when another piece is involved, but this is by no means universal usage.