| a | b | c | d | e | f | g | h | ||
| 8 |    | 8 | |||||||
| 7 | 7 | ||||||||
| 6 | 6 | ||||||||
| 5 | 5 | ||||||||
| 4 | 4 | ||||||||
| 3 | 3 | ||||||||
| 2 | 2 | ||||||||
| 1 | 1 | ||||||||
| a | b | c | d | e | f | g | h | ||
White's pawns on b5, c4, and e5 are passed pawns. Black's pawn on d4 is passed.
In chess, a passed pawn is a pawn with no opposing pawns to prevent it from advancing to the eighth rank; i.e. there are no opposing pawns in front of it on either the same file or adjacent files. A passed pawn is sometimes colloquially called a passer. Passed pawns are advantageous because only the opponent's pieces can stop them from promoting.
In the diagram, the white pawns on b5, c4, and e5 are passed pawns, and Black's pawn on d4 is a passed pawn. If Black plays ...fxg4, then the black pawn on g4 will be passed, as well as White's pawn on f4.