A "whiff" in baseball is when a batter swings at a pitch but misses the ball entirely. This is also called a "swing and a miss." When a batter whiffs, the umpire calls a strike. A whiff is an important statistic used to evaluate both pitchers and batters, as pitchers who can induce many whiffs are considered effective at deceiving batters, while batters with many whiffs might be struggling with timing or certain pitch types. The term comes from the sound or sensation of the bat swinging through the air and not hitting the ball. If a batter accumulates three whiffs in an at-bat, it results in a strikeout, and the batter is out.