Baseball Glossary


  1. a game of ball between two nine-player teams played usually for nine innings on a field that has as a focal point a diamond-shaped infield with a home plate and three other bases, 90 feet (27 meters) apart, forming a circuit that must be completed by a base runner in order to score, the central offensive action entailing hitting of a pitched ball with a wooden or metal bat and running of the bases, the winner being the team scoring the most runs. 
  2. the ball used in this game, being a sphere approximately 3 inches (7 cm) in diameter with a twine-covered center of cork covered by stitched horsehide.


Baserunner | stands on or close to first base, second base and third base at the time a pitch is thrown. Once the pitch is thrown, baserunners can try to advance to the next base — on a stolen-base attempt or after the ball is put into play. The ultimate goal of a baserunner is to score.

Batter | stand a few inches to the right or left of home plate and attempt to put the ball in play against an opposing pitcher. Right-handed batters stand on the third-base side of home plate, and left-handed batters situate toward the first-base side of the plate.

Catcher – 2 | crouches directly behind home plate and is primarily responsible for receiving all of a pitcher’s pitches.

Center Fielder – 8 | covers the middle portion of the outfield.

Closer – 1 (Pitcher) | Closers stand on the pitching mound, which is located in the center of the infield and 60 feet, six inches away from home plate. A closer is often considered the best relief pitcher that a club has in its bullpen. Closers are most often deployed for the final inning of a game when a narrow lead, three runs or less — needs to be protected.

Coach | assist their managers in decision-making.

DH – Designated Hitter | is a player who bats in place of the pitcher.

First-base Coach | stands in foul ground, just behind the first-base bag, and helps relay signals from the dugout to both batters and baserunners. 

First Baseman – 3 | positioned to the right of the first-base bag and toward the back of the infield dirt when no runner occupies first base or on the first-base bag after a batter reaches first base.

Hitting Coach | instruct players on matters related to hitting, such as batting mechanics, plate discipline and preparation.

Left Fielder – 7 | covers the left portion of the outfield grass.

Manager | responsible for writing out the daily lineup and making in-game tactical decisions (e.g. pitching changes and decisions regarding pinch-hitting, pinch-running and defensive replacements).

Official Scorer | the person appointed to observe from the press box and record the outcome of everything that happens during a game, and to make judgment calls that affect the official record of said game. The official scorer files a report after each game for documentation purposes.

Pitching Coach | instruct pitchers on pitching mechanics, pitch selection and preparation while also providing insight into the weaknesses of opposing hitters.

Relief Pitcher – 1 (Pitcher) | relief pitchers stand on the pitching mound, which is located in the center of the infield and 60 feet, six inches away from home plate. Relief pitchers enter games after the starting pitcher has been removed, usually as a result of poor performance, high pitch count or injury.

Right Fielder – 9 | covers the right portion of the outfield grass.

Second Baseman – 4 | positions himself between the first- and second-base bags (closer to second base), typically toward the back of the infield dirt.

Shortstop – 6 | positions himself between the third baseman and the second-base bag.

Starting Pitcher – 1 (Pitcher) | stand on the pitching mound, which is located in the center of the infield and 60 feet, six inches away from home plate. Starting pitchers, as the position name indicates, are the pitchers that begin each game on the mound for a team.

Tournament Commissioner – TC | Monitoring tournament organisation to ensure respect of the Norms, By Laws and the Host City Contract is being adhered to.

Third-base Coach | stands in foul ground, just behind the third-base bag, and helps relay signals from the dugout to both batters and baserunners.

Third Baseman – 5 | positions himself in the vicinity of the third-base bag, facing home plate with the base in front of him and to the right.

Umpire | responsible for enforcing on-field rules and rendering decisions on judgment calls such as: Whether a batter or baserunner is safe or out, and whether a pitched baseball is a strike or a ball.


AB – At Bat | an at-bat comes when a batter reaches base via a fielder’s choice, hit or an error (not including catcher’s interference) or when a batter is put out on a non-sacrifice. 

R – Run | a player is awarded a run if he crosses the plate to score his team a run.

H – Hit | occurs when a batter strikes the baseball into fair territory and reaches base without doing so via an error or a fielder’s choice. 

2B – Double | a batter is credited with a double when he hits the ball into play and reaches second base without the help of an intervening error or attempt to put out another baserunner. 

3B – Triple | a triple occurs when a batter hits the ball into play and reaches third base without the help of an intervening error or attempt to put out another baserunner. 

HR – Home Run | occurs when a batter hits a fair ball and scores on the play without being put out or without the benefit of an error. 

RBI – Run Batted In | a batter is credited with an RBI in most cases where the result of his plate appearance is a run being scored. There are a few exceptions, however. A player does not receive an RBI when the run scores as a result of an error or ground into double play. 

TB – Total Bases | refer to the number of bases gained by a batter through his hits. A batter records one total base for a single, two total bases for a double, three total bases for a triple and four total bases for a home run. 

AVG – Batting Average | batting average is determined by dividing a player’s hits by his total at-bats for a number between zero (shown as .000) and one (1.000). 

SLG – Slugging Percentage | represents the total number of bases a player records per at-bat. The formula for slugging percentage is: (1B + 2Bx2 + 3Bx3 + HRx4)/AB. 

OBP – On Base Percentage | refers to how frequently a batter reaches base per plate appearance. Times on base include hits, walks and hit-by-pitches, but do not include errors, times reached on a fielder’s choice or a dropped third strike. 

OPS – On Base Plus Slugging Percentage | adds on-base percentage and slugging percentage to get one number that unites the two. It’s meant to combine how well a hitter can reach base, with how well he can hit for average and for power.

BB – Base on Balls | occurs when a pitcher throws four pitches out of the strike zone, none of which are swung at by the hitter.  

HBP – Hit by Pitch | occurs when a batter is struck by a pitched ball without swinging at it. He is awarded first base as a result. Strikes supersede hit-by-pitches, meaning if the umpire rules that the pitch was in the strike zone or that the batter swung, the HBP is nullified.

SO – Strike Out | represents the number of times a batter records an out by striking out, both looking and swinging. 

GDP – Ground into Double Play | occurs when a player hits a ground ball that results in multiple outs on the bases. 

SF – Sacrifice Fly | occurs when a batter hits a fly-ball out to the outfield or foul territory that allows a runner to score.

SH – Sacrifice Hit | occurs when a player is successful in his attempt to advance a runner (or multiple runners) at least one base with a bunt.

SB – Stolen Base | number of times a player steals a base.

CS – Caught Stealing | number of times a runner is recorded as an out while attempting to steal a base.


W – Win | a pitcher receives a win when he is the pitcher of record when his team takes the lead for good — with a couple rare exceptions. First, a starting pitcher must pitch at least five innings (in a traditional game of nine innings or longer) to qualify for the win. If he does not, the official scorer awards the win to the most effective relief pitcher.

L – Loss | a pitcher receives a loss when a run that is charged to him proves to be the go-ahead run in the game, giving the opposing team a lead it never gives up.

ERA – Earned Run Average | represents the number of earned runs a pitcher allows per nine innings (or the length of the game of the category), with earned runs being any runs that scored without the aid of an error or a passed ball. 

APP – Appearance | a pitcher is credited with an appearance if he pitches in a given game. 

GS – Game Started | a pitcher is credited with a game started if he is the first pitcher to throw a pitch for his team in a given game. 

CG – Complete Game | a pitcher earns a complete game if he pitches the entire game for his team regardless of how long it lasts. 

SHO – Shutout | a starting pitcher is credited with a shutout when he pitches the entire game for a team and does not allow the opposition to score. 

IP – Innings Pitched | measures the number of innings a pitcher remains in a game. Because there are three outs in an inning, each out recorded represents one-third of an inning pitched. 

H – Hits | total hits allowed by pitcher.

R – Runs | the number of runs the pitcher has allowed, both earned and unearned. 

ER – Earned Runs | any run that scores against a pitcher without the benefit of an error or a passed ball. Often, it is the judgment of the official scorer as to whether a specific run would’ve scored without the defensive mishap.

BB – Base on Balls | refers to how many walks the pitcher has allowed. 

SO – Strike Out | occurs when a pitcher throws any combination of three swinging or looking strikes to a hitter. (A foul ball counts as a strike, but it cannot be the third and final strike of the at-bat. A foul tip, which is caught by the catcher, is considered a third strike.)

2B – Doubles Allowed | refers to how many doubles the pitcher has allowed.

3B – Triples Allowed | refers to how many triples the pitcher has allowed.

HR – Home Runs Allowed| refers to how many home runs the pitcher has allowed.

AB – At Bats Against | a count of the number of total at bats against a certain pitcher or team.

B/AVG – Opponent Batting Average | hits allowed divided by at-bats faced

WP – Wild Pitch | a pitcher is charged with a wild pitch when his pitch is so errant that the catcher is unable to control it and, as a result, baserunner(s) advance.

HBP – Hit by Pitch |times hit a batter with pitch, allowing runner to advance to first base.

BK – Balk | occurs when a pitcher makes an illegal motion on the mound that the umpire deems to be deceitful to the runner(s). As a result, any men on base are awarded the next base, and the pitch (if it was thrown in the first place) is waved off for a dead ball. 

SFA – Sacrifice Flies Allowed | refers to how many successful sacrifice flies the pitcher has allowed.

SHA – Sacrifice Hits Allowed | refers to how many successful bunts the pitcher has allowed. 

GO – Ground Outs | occurs when a batter hits a ball on the ground to a fielder, who records an out by throwing to or stepping on first base. It can also occur when the batter reaches first base — and the defence instead opts to record an out elsewhere via a “fielder’s choice.”

FO – Fly Outs | occurs when a batter hits the ball in the air and an opposing defender catches it before it hits the ground or fence.

NP – Number of Pitches | total number of pitches is determined by all the pitches he throws in live game action, including strikes, unintentional balls and intentional balls.

Types of Pitches

Changeup – CH | is one of the slowest pitches thrown in baseball, and it is predicated on deception.

Curveball – CU | is a breaking pitch that has more movement than just about any other pitch. It is thrown slower and with more overall break than a slider, and it is used to keep hitters off-balance.

Cutter – FC | is a version of the fastball, designed to move slightly away from the pitcher’s arm-side as it reaches home plate.

Eephus – EP | is known for its exceptionally low speed and ability to catch a hitter off guard.

Forkball – FO | is known for its severe downward break as it approaches the plate.

Four-Seam Fastball – FA | is almost always the fastest and straightest pitch a pitcher throws.

Knuckleball – KN | eliminates almost all of the spin on the baseball, causing it to move unpredictably on its way to the plate.

Knuckle-curve – KC | produces the desired effect of the two pitches, a slow curveball break mixed with the unpredictable movement of the knuckleball.

Screwball – SC | a breaking ball designed to move in the opposite direction of just about every other breaking pitch.

Sinker SI | a pitch with hard downward movement, known for inducing ground balls. 

Slider – SL | a breaking pitch that is thrown faster and generally with less overall movement than a curveball. 

Splitter  FS | thrown by gripping the ball with his two fingers “split” on opposite sides of the ball. When thrown with the effort of a fastball, the splitter will drop sharply as it nears home plate.

Two-Seam Fastball -FT | is slower than a four-seam fastball, but has more movement. With a two-seam fastball, the ball moves in the same direction as whichever arm is being used to throw it.


C – Chances | Represent the number of opportunities he/she has to record an out. The formula for chances is: assists plus putouts plus errors.

PO – Put Outs | a fielder is credited with a putout when he is the fielder who physically records the act of completing an out – whether it be by stepping on the base for a forceout, tagging a runner, catching a batted ball, or catching a third strike. 

A – Assists | Awarded to a fielder who touches the ball before a putout is recorded by another fielder.

E – Errors | A fielder is given an error if, in the judgment of the official scorer, he fails to convert an out on a play that an average fielder should have made.

FLD% – Fielding Percentage | Answers how often does a fielder or team make the play when tasked with fielding a batted ball, throwing a ball, or receiving a thrown ball for an out. The formula is simple: the total number of putouts and assists by a defender, divided by the total number of chances (putouts, assists and errors).

DP – Double Play | occurs when two offensive players are ruled out within the same play. 

SBA – Stolen Bases Allowed (Pitcher and Catcher) | number of times a runner successfully stole a base.

CSB – Caught Stealing (Pitcher/Catcher) | number of times a runner was caught stealing. 

SBA% – Stolen Bases Against Percentage (Pitcher and Catcher) | refers to the frequency with which a catcher/pitcher throw out opposing baserunners who are trying to steal. The formula is simple: CSB divided by total stolen-base attempts (both successful and unsuccessful) against that catcher/pitcher. 

PB – Passed Ball (Catcher) | a catcher is given a passed ball if he cannot hold onto a pitch that, in the official scorer’s judgment, he should have, and as a result at least one runner moves up on the bases.

CI – Catcher’s Interference | when a catcher (or any other fielder) interferes with a batter at any point during a pitch, the batter is awarded first base if the catcher.


Ace | refers to a team’s best pitcher, though it can also be used to describe an elite pitcher in general. Therefore, a team with multiple elite pitchers is said to have more than one ace.

Appeal Plays | the defensive team can appeal certain plays to alert the umpires of infractions that would otherwise be allowed without the appeal. 

Balk | is an illegal act by the pitcher when one or more runners are on base.

Batter’s Box | A regulation baseball field has two batter’s boxes — one on the left side and one on the right side of home plate.

Catcher’s Interference | the batter is awarded first base if the catcher (or any other fielder) interferes with him at any point during a pitch.

Can of Corn | a routine fly ball hit to an outfielder.

Collision at Home Plate | the baserunner is not allowed to deviate from his direct path to initiate contact with the catcher (or any player covering the plate).

Dead Ball | is a ball that is out of play.

Designated Hitter Rule – DH | the designated hitter rule allows teams to use another player to bat in place of the pitcher. 

Fair Ball / Foul Ball | the foul lines and foul poles are used to demarcate fair territory and, thus, determine what constitutes a fair ball.

Force Play | occurs when a baserunner is no longer permitted to legally occupy a base and must attempt to advance to the next base.

Infield Fly | any fair fly ball (not including a line drive or a bunt) which can be caught by an infielder with ordinary effort when first and second or first, second and third base are occupied, before two men are out.

K | a strikeout.

Obstruction | an act by a fielder, who is not in possession of the ball or in the process of fielding it, that impedes the baserunner’s progress.

Pickle | a rundown.

Southpaw | a left-handed pitcher.

Strike Zone | is the area over home plate from the midpoint between a batter’s shoulders and the top of the uniform pants, when the batter is in his stance and prepared to swing at a pitched ball, and a point just below the kneecap. In order to get a strike call, part of the ball must cross over part of home plate while in the aforementioned area.

Walk-off | any offensive play that gives the home team the lead, and thus, the win, in the bottom of the last inning