Definitions
1.NounThe back.
2.NounThe act of taking back or going back on a statement, promise, or agreement.
3.NounA reciprocal action or consequence, such as immediately tagging the player who has tagged one in a game of tag.
4.NounThe act of going through a sequence of moves in reverse.
5.NounThe act of joining a queue behind a friend rather than at the end of the queue.