Baseball Terminology: A Plain-English Guide to the Words of the Game
A clear guide to baseball terminology, from strikes, balls and balks to force plays, infield flies and the stats on every box score, using the official rules.
Baseball terminology is the game’s basic vocabulary. An inning is the part of a game where each team bats once and fields once, and an out is one of the three retirements that end a team’s turn at bat. A run counts once a batter gets on base and goes on to touch every base in turn, ending at home plate, a strike is a pitch the umpire calls against the batter, such as a swing and a miss, and a ball is an unswung pitch that never crosses the strike zone in the air. These meanings come from the Definitions of Terms in MLB’s Official Baseball Rules.
The Basic Building Blocks of a Game
Each side needs three putouts before its turn in an inning ends, and one team’s turn at the plate is known as a half-inning. The rules also call a run a score.
There are four bases, and a runner has to touch each of them to score. Any offensive player heading for a base, standing on one, or going back to one counts as a runner.
Words for Pitches
When the pitcher throws the ball to the batter, that throw is a pitch.
Strike, Ball and the Strike Zone
The umpire calls a strike on a legal pitch in several cases. The main ones are a swing and a miss, a pitch the batter lets go by while part of it crosses the strike zone, and a foul hit with fewer than two strikes already counted. A ball is the opposite case: the batter does not swing, and the pitch never passes through the zone in the air. A pitch that hits the dirt first and then bounces through the zone still counts as a ball.
The strike zone sits over home plate. Its upper edge is a level line halfway between the top of the batter’s shoulders and the top of their pants. Its lower edge is at the hollow under the kneecap. The umpire judges it by how the batter stands when ready to swing at a pitch.
Walks, Wild Pitches and Balks
A base on balls, more often called a walk, gives the batter first base once four pitches have missed the strike zone. The defensive manager can also signal the umpire that the batter is to be walked intentionally, and the umpire then awards first base.
A wild pitch misses so badly, whether high, low or wide, that the catcher cannot handle it with ordinary effort. A passed ball is charged to the catcher instead, when the catcher’s own action lets one or more runners move up.
With at least one runner on base, certain illegal moves by the pitcher are called a balk. Each runner then gets to move up one base.
Words for Batted Balls
The rulebook sorts batted balls by their path:
- A fly ball rises high in the air.
- A ground ball stays near the ground, rolling or bouncing.
- A line drive goes straight and hard off the bat and reaches a fielder before it ever hits the ground.
- A bunt is a ball the batter meets on purpose without swinging, tapping it slowly so it stays in the infield.
Where the ball ends up decides whether it is in play. A fair ball covers several cases: the ball stops in fair ground inside the first-base or third-base line before reaching those bases, it hits first, second or third base, its first bounce is in fair ground at or past first or third, or it leaves the park in the air over fair ground. A foul ball is the matching case in foul territory. For a foul fly, the umpire looks at where the ball is relative to the foul line and foul pole, not where the fielder happens to be.
Words for Defensive Plays
A tag is made in one of two ways: the fielder touches a base while firmly holding the ball, or touches the runner with the ball, or with the glove or hand that has the ball in it. In a force play, a runner no longer has the right to stay on a base because the batter has become a runner.
Getting two offensive players out in one continuous play is a double play, and getting three is a triple play, provided there is no error in between the outs. When fielders chase a runner who is trapped between two bases, it is a run-down.
A fielder’s choice happens when a fielder handles a fair ground ball and decides not to throw to first for the batter-runner, throwing to another base instead to try to retire a runner who was already on.
The Infield Fly Rule
An infield fly is called on a fair fly that an infielder could catch with ordinary effort. It applies only with fewer than two outs and with runners on first and second, or with the bases loaded. Line drives and attempted bunts are not included. The rulebook says the umpire calls “Infield Fly” right away, and that this is done “for the benefit of the runners.” Once it is declared, the batter is out.
Scoring and Statistics Terms
Some of the scoring terms that come up most:
- Run batted in: a batter gets credit when what they do at the plate makes a run score, for example a hit, a sacrifice fly, or a walk with every base already occupied.
- Stolen base: a runner gets credit for moving up one base on their own, with no help from a hit, putout, error, force-out, fielder’s choice, passed ball, wild pitch or balk.
- Strikeout: when the umpire calls strike three, the pitcher is credited with a strikeout and the batter is charged with one.
- Earned run: a run the pitcher is responsible for. The scorer works it out by rebuilding the inning with the errors and passed balls taken out.
A slash line writes three hitting numbers in a row, separated by slashes, in the order AVG/OBP/SLG: batting average first, then on-base percentage, then slugging percentage. Slugging percentage measures how many bases a hitter gets per at-bat. It does not treat all hits as equal, so a double, triple or home run is worth more in it than a single.
Frequently Asked Questions
Where are official baseball terms defined?
MLB’s Official Baseball Rules include a Definitions of Terms section that covers words such as strike, ball, balk and infield fly. Scoring words like earned run, stolen base and run batted in are covered in the rulebook’s section on the official scorer.
What is the difference between a wild pitch and a passed ball?
A wild pitch goes on the pitcher’s record, when a pitch is too far off for the catcher to handle with ordinary effort. A passed ball goes on the catcher’s record, when the catcher’s own action lets a runner move up.
What happens when the umpire calls an infield fly?
The batter is out as soon as the umpire declares it. The rulebook says the umpire makes the call to help the runners.
