strikeout

right|thumb|250px|Cincinnati Reds outfielder [[Adam Dunn strikes out swinging.]]In baseball or softball, a strikeout (or strike-out) occurs when a batter accumulates three strikes during a time at bat. It means the batter is out, unless the third strike is not caught by the catcher and the batter reaches first base safely as a result. A strikeout is a statistic recorded for both pitchers and batters, and is usually denoted by the letter K, or sometimes by the initialism SO. A "strikeout looking"—in which the batter does not swing and the third strike is called by the umpire—may be denoted by an inverted K (i.e. ꓘ).

Although a strikeout suggests that the pitcher dominated the batter, the free-swinging style that generates home runs also leaves batters susceptible to striking out. Some of the most prolific home run hitters of all time (such as Adam Dunn, Mickey Mantle, Reggie Jackson, Alex Rodriguez, and Jim Thome) were notorious for striking out often. Notably, Jackson and Thome respectively hold the major league records for most and second most times struck out in a career. Conversely, Tony Gwynn who is notorious for his strikeout statistics amassing only 434 strikeouts in 10,232 plate appearances over his 20-year playing career, was also noted for his lack of home runs.