A pawn that has been left behind by neighboring pawns and cannot obtain support from other pawns. Without nearby pawns to advance and protect it, it becomes isolated and vulnerable. The square in front of it can be used as an outpost by the opponent. It is susceptible to attacks from long-range pieces like rooks and bishops. It becomes particularly weak when on open or semi-open files. Difficult to defend, it often becomes a long-term positional weakness

A pawn whose advance is obstructed by a piece. Knights are considered the ideal blockers, while queens and rooks are generally unsuitable for blocking. This refers not just to being blocked, but to being immobilized in a strategically disadvantageous way

Pawns on a file where opposing pawns face each other and cannot advance. These contribute to creating a closed position

A square not defended by pawns that can easily be used as an outpost by opponent's pieces. Likely to become an outpost for opponent's knights or bishops, and cannot be easily driven away by your pieces. Strategically controlling such squares provides significant advantages

A pawn with no friendly pawns on adjacent files, making it isolated. It tends to become a weakness as it cannot be supported by other pawns. When it's a d-pawn, it's called an Isolated Queen's Pawn (IQP)

A phenomenon where (for White) a bishop becomes trapped on a2 and cannot move

A colloquial abbreviation for Passed Pawn, commonly used in casual speech, game commentary, and English-speaking chess conversations

Groups of pawns that are not connected to each other (isolated). When vertically adjacent pawns are broken, the resulting isolated pawn groups are called islands. The more pawn islands, the more vulnerable the structure tends to be

According to Hans Kmoch's definition in Pawn Power in Chess (1956), the distance between the back rank and a pawn

An expression describing a pawn structure that has been broken into pieces. Particularly refers to formations with mixed doubled pawns, isolated pawns, and tripled pawns that lack cohesion and are difficult to defend