Baseball Terms | List & Definitions

As one of the most popular sports in the US and a regular feature in the Summer Olympics, baseball has a language all its own. From casual neighborhood games to the World Series, baseball terms like “home run” and “strikeout” are essential for understanding the game.

Baseball’s reach continues to expand, with professional leagues in Japan, Mexico, and beyond, so its unique lingo has become increasingly global. The World Series, in particular, draws attention from fans worldwide. And terms like “curveball” and “step up to the plate” are common metaphors in everyday English.

In this beginner-friendly guide, you’ll learn the key baseball terms and what to expect during a typical game so that you can enjoy baseball no matter where or when you’re watching. QuillBot’s AI Chat can also answer questions about baseball, and it’s completely free to use.

How does baseball work?

A baseball game involves two teams of nine players each, competing to score the most runs (points earned when players circle the baseball field). Each run around the baseball diamond is worth 1 point. The corners of the baseball diamond are marked with three bases (first, second, third) and a home plate (the start and end point of a run).

Each game is divided into nine segments, called innings.

• For the first half of an inning (aka the top of the inning), one team hits the ball and runs around the bases, and the other team tries to prevent them from scoring.
• For the second half (aka the bottom), the teams reverse roles.

A top or bottom of an inning includes these steps:

• Players on the offensive team take turns batting the ball at home plate.
• The pitcher on the defensive team pitches the ball to a batter, who has three chances to hit the ball with the bat. Each missed chance is called a strike. Three strikes lead to an out. After three outs, the teams switch offense and defense.
• Hitting the ball earns the batter the right to start running to first base (unless a defensive player catches the ball mid-air, in which case the batter is immediately out).
• While the runner progresses toward first base (or beyond), the defensive team can get the runner out in one of two ways:
  • Touch the runner with the ball between bases
  • Touch the base while holding the ball before the runner arrives (e.g., when the runner is between second and third)
• If a runner gets to a base before the above happens, the runner is safe. Runners strategically decide when to stop at first base, progress to second base, etc., based on the location of the ball and the defense’s performance.
• If a batter/runner finishes their turn on first, second, or third base, the next offensive player takes a turn batting, and the process continues. When the next player hits the ball, a player on first base can progress to second base or further.
• When someone is batting, and there are already players on first, second, and third base, the bases are loaded, which gives the team terrific odds for scoring at least one run (or four runs if that batter gets a home run).
• Runners can also steal a base while the pitcher is delivering the ball to the batter, and they can be tagged out while stealing (aka caught stealing).

Baseball field terms

Many baseball terms refer to the different parts of a baseball field.

• Dugout: Where players on the offensive team wait for their turns to bat
• Home base (aka home plate): Where the batter stands to receive pitches and hit the ball; also the end point for a full run around the baseball diamond
• Bases (first, second, third): Three 18×18” sandbags placed at each corner of the diamond (besides home base) to mark where a runner is safe from being tagged out
• Infield: The part of a baseball field that includes the bases and home plate plus a dirt area just outside of first, second, and third bases
• Baselines: The (invisible) lines between the bases that mark the perimeter of the infield or diamond
• Pitcher’s mound: The dirt mound at the center of the infield where the pitcher stands
• Catcher’s box: A box behind home plate where the catcher squats to catch the balls that the hitter misses
• Outfield: The area of a baseball field that’s outside of the infield, which is usually covered by turf and includes left field, right field, and center field (the areas where certain defensive players stand)
• Foul lines: The boundary lines extending in each direction from home plate to determine whether a hit is a foul ball or a fair ball

Baseball positions

Baseball teams include several positions, especially for the players who cover different parts of the field during defense.

• Umpire: The official who makes judgment calls on foul/fair balls, strikes, and outs (also the person who shouts, “Play ball!” at the start of each MLB game)
• Baserunner: A player on the offensive team who is trying to advance from one base to the next
• Fielder: Any player on the defensive team who is trying to prevent hitters and baserunners from scoring
• Infielders: The fielders who play on the infield, which usually involves catching throws from other defensive players and tagging the bases to get outs
• Pitcher: The fielder who pitches the ball to the batter to begin each play
• Catcher: The fielder who stands behind the batter to catch pitches that aren’t hit and defends home base from runners attempting a home run
• First baseman: An infielder who defends first base, which is especially important because first base is the first milestone for a complete run
• Second baseman: Defends second base
• Third basemen: Defends third base
• Shortstop: The infielder who plays between second and third base
• Outfielders: The right fielder, left fielder, and center fielder, who play defense in those areas of the outfield (e.g., to catch a fly ball for an out or throw the ball to the infielders to tag runners out)
• Designated hitter: A player whose only job is to bat in place of the pitcher (who usually doesn’t hit because of the skill and effort that pitching entails)

Baseball terms for hits and strikes

“Three strikes, you’re out” is fundamental in baseball, but the rules about hits and strikes are quite detailed. Batters and pitchers leverage these rules to outsmart each other. For example, the pitcher tries to deceive the batter into taking swings that lead to strikes, fouls, or unsuccessful hits. The baseball terms below show how this works.

• Strike zone: This area between the player’s shoulders and knees determines which pitches the batter is obligated to try and hit.
  • If a pitch is in the strike zone, the batter must swing or get a strike.
  • If a pitch is outside the strike zone, the batter can do nothing and wait for the next pitch or take a swing, which may or may not lead to an out.
• Ball: When the batter ignores a pitch that is outside the strike zone, the umpire announces “ball,” and the batter doesn’t get a strike.
• Walk: If the batter gets four balls before a third strike, the batter automatically progresses to first base. There is no running because the fielders cannot tag the batter out in this situation.
• Strike out: After three strikes, a batter strikes out and returns to the dugout. A strikeout counts towards the three outs that cause the team to switch from batting to defense.
• Foul ball: When a batted ball lands outside the foul lines, the consequences depend on how many strikes the batter already has.
  • A foul ball is a strike if the batter hasn’t gotten two strikes yet.
  • If the batter already has two strikes, a foul ball is not a strike unless the batter bunted the ball (lightly tapped it into the infield).
  • If a fielder catches any foul ball before it touches the ground, the batter is out.
• Base hit (aka single): The batter safely reaches first base.
• Double: The batter reaches second base safely (without getting tagged out).
• Triple: The batter safely reaches third base.
• Home run: The batter safely makes it back to home plate after batting.
• Based loaded: The batter has teammates on first, second, and third base (who will progress further if the batter is successful).
• Grand slam: The batter makes a home run with the bases loaded, which results in four runs (4 points).

Baseball terms for defensive plays

While the offensive team focuses on batting and running, the defense’s goal is to prevent runs and get three outs as quickly as possible. Fielders rely heavily on teamwork, quick thinking, and precise throws. These baseball terms describe the different types of outs.

• Flyout: Catching the batted ball (aka a fly ball) in the air before it touches the ground
• Tag out: Touching a runner with the ball (or glove holding the ball) before they reach the base
• Force out: Getting a runner out by stepping on the base (while holding the ball) before they reach the base
• Double play: Two outs made during one continuous play (e.g., when there are runners on more than one base)
• Triple play: Three outs made during one play (rare)
• Groundout: Fielding a ground ball and throwing it to the base for an out

MLB team names

Major League Baseball (MLB) in the US has a total of 30 baseball teams, each with a loyal and vibrant fanbase.

• Arizona Diamondbacks
• Athletics (intentionally omits a city/state as part of its brand identity)
• Atlanta Braves
• Baltimore Orioles
• Boston Red Sox
• Chicago Cubs
• Chicago White Sox
• Cincinnati Reds
• Cleveland Guardians
• Colorado Rockies
• Detroit Tigers
• Houston Astros
• Kansas City Royals
• Los Angeles Angels
• Los Angeles Dodgers
• Miami Marlins
• Milwaukee Brewers
• Minnesota Twins
• New York Mets
• New York Yankees
• Philadelphia Phillies
• Pittsburgh Pirates
• San Diego Padres
• San Francisco Giants
• Seattle Mariners
• St. Louis Cardinals
• Tampa Bay Rays
• Texas Rangers
• Toronto Blue Jays
• Washington Nationals

Baseball terms slang

Superfans and sportscasters use a variety of slang terms for different techniques and outcomes. These are just a few of the slang terms that come up in baseball banter.

• Airmail: When a fielder throws a ball to a teammate, but it flies high over that player’s head
• Aspirin: A fastball that is so fast that it’s almost impossible to hit (like a tiny aspirin tablet would be)
• Dot: To hit the batter with a pitched ball
• Free baseball: Fan slang for extra innings
• Large sausage: A grand slam home run
• Wheelhouse: The area of a strike zone where a batter performs best

Famous baseball quotes

Because of its long and rich history, the world of baseball is full of quotes from legendary players, blockbuster baseball films, and team managers.

• “There’s no crying in baseball.”  —A League of Their Own
• “How can you not be romantic about baseball?”  —Moneyball
• “Set your goals high, and don’t stop ‘til you get there.” —Bo Jackson
• “Baseball is 90 percent mental. The other half is physical.” —Yogi Berra
• “It ain’t over ‘til it’s over.” —Yogi Berra
• “Life is not a spectator sport.”  —Jackie Robinson
• “A life is not important except in the impact it has on other lives.”  —Jackie Robinson
• “I’d walk through hell in a gasoline suit to play baseball.” —Pete Rose
• “Never let the fear of striking out get in your way.”  —Babe Ruth
• “Don’t let people tell you what you can’t do.” —Kim Ng
• “Baseball is the only field endeavor where a man can succeed three times out of 10 and be considered a good performer.”  —Ted Williams
• “A ball player has to be kept hungry to become a big leaguer. That’s why no boy from a rich family has ever made the big leagues.” —Joe DiMaggio
• “There is no room in baseball for discrimination. It is our national pastime and a game for all.” —Lou Gehrig

Frequently asked questions about baseball terms

What are some baseball pitching terms?

Baseball pitchers use a variety of different pitches to make the hitter’s job harder (and prevent the other team from scoring). There are several baseball pitching terms for these techniques.

• Fastball: Moves very fast, which gives the hitter less time to react
• Curveball: Moves slowly, down, and to the side (also an idiom for an unexpected challenge in real life)
• Changeup: Looks like a fastball but is actually slow (in order to deceive the hitter)
• Knuckleball: Has a lot of spin, which is less predictable
• Euphus: A very slow pitch with a high arch
• Splitter: A fastball that moves downward
• Slider: Similar to a curveball, but fast

Whether you’re new to baseball or brushing up on baseball terms, QuillBot’s free AI Chat can provide instant answers about all things baseball.

Is it World Series or World’s Series?

The name of the Major League Baseball (MLB) championship is the World Series (with no apostrophe). “World” is a singular noun, and it’s not possessive. People sometimes mistakenly write “World’s Series,” because the event used to be called the “World’s Championship Series.”

These types of mistakes are common, but luckily, QuillBot’s free Grammar Checker can help you with correct spelling and punctuation.

Why is it called the World Series in baseball?

Because the World Series only involves US teams (and one Canadian team), it’s no wonder that people often ask how the World Series got its name.

It’s called the World Series because when the first event took place in 1903, the US was the only place in the world with professional baseball games. Therefore, the winning team at that time would be the literal world champion. Now, baseball is an Olympic sport, and there are international baseball leagues.

When you’re curious about baseball’s history or baseball terms, QuillBot’s free AI Chat can instantly answer your questions.

What are some common sports idioms?

Some of the most common sports idioms in English include:

• Down-and-out (boxing): Physically or financially weakened like a boxer who has been knocked down and is unconscious
• Drop the ball (baseball, rugby, American football): To forget to do something or miss an opportunity
• Gambit (boxing and chess): A calculated move
• Get the ball rolling (various ball games): To start an activity
• Hands down (horse racing): Unquestionably
• Have (someone) in your corner (boxing): To have someone’s support or help
• Hit below the belt (boxing): To criticize another person in an unfair or unethical way
• Keep your eye on the ball (baseball): Stay alert
• Mulligan (golf): A do-over
• On the ball (baseball): Alert and proactive
• Par for the course (golf): Normal or expected
• Roll with the punches (boxing): To gracefully triumph over any challenges that come along
• Saved by the bell (boxing): To get out of a difficult situation because of a timely interruption
• Slam dunk (basketball): A certain win or guaranteed success

When you’re curious about the origin or meaning of different sports idioms, QuillBot’s AI Chat will provide instant answers, and it’s completely free to use.