The term TAT can refer to two different things. The first is RATA, which is an acronym for Rapid Air Transportable Aircraft. This type of aircraft is designed to be quickly transported by air and used in a variety of military operations. The second is TITFOR, which stands for Tit-for-Tat. This is a strategy used in game theory where one player responds to the other's move in kind. It is often used to create a balance of power between two players.