In baseball, a strikeout or strike out (denoted by K or SO) is an out made when the batter receives three strikes during his time at bat.
Strikeouts are associated with dominance on the part of the pitcher and incompetence on the part of the batter, although for power hitters it is recognized that the style of swing that generates home runs also leaves the batter somewhat susceptible to striking out.
In scoring, a swinging strikeout is recorded as a forwards K, and a strikeout on a called third strike is recorded as a backwards K.
Slang terms for swinging strikeouts include whiff and blow away. For taking a called third strike, slang includes punchout and catch looking.
A pitcher is said to "strike out the side" when he retires all three batters in a half inning by striking them out, usually, but not necessarily, in a row.
When a batter strikes out three times in a game, he is said to have completed a "hat trick". If he strikes out four times, it is a "golden sombrero" or a "silver sombrero". He receives the "Olympic rings" for striking out fives times and the "horn" for striking out a rare six times in a game.
Season and career strikeout totals for pitchers are followed closely by fans. The top 5 Major League Baseball career strikeout leaders:
- Nolan Ryan - 5714
- Steve Carlton - 4136
- Roger Clemens - 4099†
- Randy Johnson - 3871†
- Bert Blyleven - 3701
- Nolan Ryan, 1973 - 383
- Sandy Koufax, 1965 - 382
- Randy Johnson, 2001 - 372†
- Rube Waddell, 1904 - 349
- Bob Feller, 1946 - 348
- †Denotes active player