Connected pawns are two or more pawns of the same color placed on adjacent files, able to support each other as they advance.
This structure is considered one of the healthiest in chess: each pawn protects its neighbour diagonally. For instance, white pawns on d4 and e4 are connected — the e4 pawn controls d5, and if a black pawn arrives there, e4 can capture it (exd5), actively defending the structure. More generally, connected pawns can cover each other’s key squares, making them hard to attack in isolation.
In practice, aim to keep your pawns connected throughout the game. Avoid exchanges that leave a pawn stranded with no neighbours on adjacent files, as an isolated pawn becomes a long-term weakness the opponent can target at will. The connectivity of your pawns is a reliable indicator of how solid your position truly is.