A dice pool is a type of game mechanic which uses a variable number of dice thrown as a group in order to determine the outcome of a game event. In most implementations, the number of dice thrown increases as the skill of the character increases. Usually, the goal is to score many successes as the attempted action requires, but some games sum the dice to achieve some threshold or use a variation such as the roll-and-keep system found in Legend of the Five Rings.
Some gamers dislike dice pool mechanics because they find rolling a large number of dice to be unwieldy, particularly in games such as Exalted or Shadowrun where the dice pools can grow very large indeed. Conversely, other gamers like dice pools because they prefer bell-curve probabilities over the linear probabilities of single-die mechanics and the visceral feeling of throwing lots of dice.