Protected Passed Pawn
Protected Passed Pawn,
a passed pawn that is protected by a friendly pawn, and thus gaining some extra "long range" bonus in evaluation since it might become a decisive winning advantage in pawn endgame assuming other things being equal . In pawn endings, a protected passed pawn typically obligates the opponent king inside its square of the pawn, which makes the defender taboo to capture by the king, freeing the own king from defensive duties.
If the defending pawn is even a passed pawn by itself, the passers are connected . The defender may advance at times to establish a connected duo, mutually protecting their stop squares with the option to advance the one or the other passer for a protected passed pawn one rank further. As pointed out by Robert Hyatt , one should be careful in evaluating connected passers versus two distant isolated passers.