The term 'Poker Prerequisite' can be summarized as a requirement to play poker, and the four-letter solution to this term is 'ante'. An ante is a forced bet that each player must make before the start of a hand in order to create an initial pot. This is done to ensure that there is something to play for and to encourage players to stay in the game. Antes are usually a small fraction of the minimum bet, and they are typically used in games with more than two players.