Skewers are chess tactics that are the opposite of pins. Whereas a pinned piece is stuck against another piece, a skewer works by pushing away the enemy piece in front, in order to capture the enemy piece behind it. Skewers can work on diagonals (by Bishops and Queens) or along ranks and files (by Rooks and Queens). You cannot do a skewer with a Knight, Pawn, or King.
Related Chess Tactics
Read more about these related chess tactics and strategies: