Online poker tournaments

Some of the common poker definitions are as follows:

Prize Pool: It is defined as the total amount a winner of the poker tournament would get, after winning the game
Freeroll tournament: A freeroll tournament offers 0$ buy-in. A player need not invest extra amount from his pocket, to play the pot.
Buy-in is defined as the amount a player has to have, to play the tournament to the final round. Buy-in is not related to fee charged from the player.

There are many other poker tournament definitions, but these are the most commonly used.