The term is part of the essential and basic backgammon dictionary, it refers to the in-game situation when one of the players hits or is hit. This term is not so widely used, because it is an umbrella term both for hitting and being hit, and the players like to use the specific words, but it is a very important one, so even the beginner players should be aware of its meaning. As you can see, the meaning of the term is quite close to the basic meaning of the word, because in both cases there is contact between the checkers.