Isolani

In chess, an isolated pawn is a pawn which has no friendly pawn on an adjacent file. An isolated queen's pawn is often called an isolani. Isolated pawns are usually a weakness because they cannot be protected by other pawns. Many "textbook" openings create at least one isolated pawn but are nevertheless accepted as orthodox because they create advantages, such as improved development and associated opportunities for counterplay, that offset or even outweigh the weaknesses associated with the pawn's isolation.