In football and basketball, to "kill the clock" means to stop the game clock. Both sports use a clock for time limits (for each quarter or half). As time is running out before the end of a period, teams often try to get in an extra play or try to score before the end. Teams try to "kill" or "stop" the clock by calling a timeout; or, in football, by running out of bounds or deliberately "grounding" the ball (to stop the game clock). Using the clock wisely in this manner gives the team an extra play or two in order to score last second points.