Connected Pawns
The most favorable position of two Pawns is side by side. In the diagram, the b- and c-Pawns for both sides are connected (sometimes called united).
Isolated Pawns
In sharp contrast to the strength of connected Pawns is the weakness of isolated Pawns. These are Pawns which have no friendly Pawn on either adjacent file.
Backward Pawn
Another example of a weak Pawn is shown in this diagram. The b-Pawn is backward because it lags the Pawn to its side and can no longer be protected by any other Pawn.
Doubled Pawns
Pawns of the same color on the same file, like the White c-Pawns in the diagram, are called doubled Pawns. Their particular weakness is that they are unable to create a passed Pawn by force. The single Black Pawn easily blocks its two adversaries.
Pawn majority
Pawn chain
Hanging Pawns
Connected Pawns, one passed