This is a widely used strategy in backgammon, and the term has two meanings. As a noun, it has the meaning of a point occupied by two, or even more checkers, which the player had placed there to block the opponent player’s progress.

As a verb, it means that one of the players tries to prevent forward movements of the opponent player, by placing checkers on a blocking point. In order to block the opponent player, you will have to place checkers in front of the opponent’s checkers.