BATTING AVERAGE (AVG)
The batting average of an individual player is calculated by dividing base hits by at-bats (AB). Walks, hit-by-pitch, and sacrifice hits are not counted as an official at-bat.

HOME RUNS (HR)
A home run is defined as a hit that either clears the outfield wall in the air or a hit that stays within the confines of the field resulting in the batter scoring, without the benefit of an error, such as an inside the park home run.

RUNS BATTED IN (RBI)
A Run Batted In occurs when a player's batted ball results in another player crossing the plate. For a HR, the hitter would also receive a RBI because he bats himself in. RBI's are a good measure of a batter's ability, but is situationally dependent. Opportunities are higher for a player depending on his slot in the batting order and the batters that precede him.

RUN OR RUN SCORED (R)
A run scored is when a player advances through the bases and crosses home plate. Like RBI's, runs scored for a player are very dependent upon his teammates, unless the player hits a HR and generates a run by his own doing.

STOLEN BASES (SB)
In general, a stolen base occurs whenever a runner advances one base without benefit of a hit, an error, a putout, a fielder's choice, a passed ball, a balk or a wild pitch. There are several other stipulations for a stolen base to be credited, but this is the general rule.

ON-BASE PERCENTAGE (OBP %)
On-base percentage is a measure of how often a player reaches base via a hit, walk, or hit-by-pitch. (Hits + BB + Hit by pitch) / (AB + BB + Hit by pitch + Sacrifice flies)

SLUGGING PERCENTAGE (SLG %)
Slugging percentage is a statistical measure of a batter's effectiveness in making extra-base hits. A single is worth one base; a double, two; a triple, three; and a home run, four. Slugging percentage is total bases divided by at-bats.

ON-BASE PLUS SLUGGING PERCENTAGE (OPS%)
A reasonably accurate and easily calculated index of a hitter's rate of offensive production. Sometimes represented as OBP+SLG, as it combines those two basic offensive skills. It is becoming a very popular fantasy baseball scoring category.

Win (W)
A win is credited to the starting pitcher only if he has pitched at least five complete innings, leaves the game with the lead and his team holds the lead for the remainder of the game. A win is credited to the relief pitcher if, while he is still in the game, his team takes the lead and stays ahead for the remainder of the game. No more than one win is credited each game.

SAVE (SV)
A save is credited to the pitcher who protects a lead for another pitcher and finishes the game under one of these three situations: 1. Enters the game with the lead of no more than three runs and pitches for at least one inning. 2. Enters the game, regardless of the count, with the potential tying run either at bat, on base, or on deck. 3. He pitches effectively for at least three innings. No more than one save is credited in each game.

STRIKEOUTS (SO or K)
A strikeout is credited to the pitcher whenever he delivers a third successful pitch at which the batter swings and misses, or which the umpire calls a strike. A strikeout is also credited in the case of a two-strike foul bunt attempt or a passed ball or wild pitch on the third strike.

EARNED RUN AVERAGE (ERA)
Earned run average is a measure of the efficiency of a pitcher by multiplying earned runs allowed by nine, then dividing by that pitcher's innings pitched.

WHIP RATIO (WHIP)
The "WHIP" ratio stands for "Walks, Hits, Innings Pitched." This ratio determines the average number of hits and walks allowed per inning by any given pitcher. Walks + Hits divided by the number of Innings Pitched.

ACE
A team's best starting pitcher.

AGE 27 RULE
The age at which an unusually high percentage of players have their best seasons. As a consequence, when people devise such career projections systems as Bill James', the best season will compute out to be age 27. Not all players have their career years at age 27. But maybe 30% do have them then, and that is clearly the best figure for any age. When you add in the ones that have their career years at age 26 and 28, that three-year period is clearly the peak for Major League Baseball players.

ALLEY
The section of the outfield between the outfielders. Also called gap.

AROUND THE HORN
A double play going from third base to second base to first base.

ASSIST
Help from a fielder in putting an offensive player out. A fielder is credited with an assist when he throws a baserunner or hitter out at a base.

AT BAT
Each Batter’s opportunity at the plate is scored as an "at bat" for him.

BACKSTOP
Fence or wall behind home plate.

BAG
Slang-term for a base.

BALK
Penalty for an illegal movement by the pitcher. The rule is designed to prevent pitchers from deliberately deceiving the runners. If called, baserunners advance one base.

BALL
A pitch outside the strike zone.

BASE
One of four “stations” to be reached by the runner.

BASEBALL
The baseball’s core is made of rubber and cork. Yarn is wound around the rubber and cork centre. Then 2 strips of white cowhide are sewn around the ball. Official baseballs must weigh 5 to 5 1/4 ounces and be 9 to 9 1/4 inches around.

BASE HIT
A play in which the batter hits the ball in fair territory and reaches at least first base before being thrown out.

BASE ON BALLS (Also known as a “walk”)
Four balls and the hitter advances to first base.

BASE COACH
A coach who stands by first or third base. The base coaches instruct the batter and base runners what to do with a series of hand signals.

BASE LINE
The white chalk lines that extend from home plate through first and third base to the outfield and up the foul poles, inside which a batted ball is in fair territory and outside of which it is in foul territory.

BASES EMPTY
No runner on the bases.

BASES LOADED
Runners are on first, second and third base.

BAT
Instrument used by the hitter while batting. The bat must be no longer than 42 inches and no wider then 2 3/4 inches. Players are allowed to cover the first 8 inches of the bat’s handle so they can grip it better.

BATTER
An offensive player who takes his position in the batter’s box.

BATTER’S BOX
An area marked by white chalk lines on the left and right side of home plate in which a player must stand while batting.

BATTERY
Term referring to the pitcher and catcher combination.

BATTING ORDER
The offensive line-up of a team that lists the player will bat. The batting order is given to the umpire before each game.

BLOWN START
Any start where a pitcher lasts less than five innings and allows five or more earned runs.

BOX SCORE
The progression of the game as written in a series of boxes indicating hits, runs, errors and player substitutions of each inning played.

BREAKING BALL
An off-speed pitch that curves.

BRUSHBACK
A pitch that nearly hits the batter.

BULLPEN
Area designated for pitchers to warm-up.

BUNT
Short hit that is executed by letting the ball hit the bat (not swinging). Usually attempted to advance a runner.

CALLED GAME
A game suspended or ended by the umpire.

CAN OF CORN
An easy catch by the fielder.

CAUGHT LOOKING
When a batter is called out on strikes.

CATCHER
Player positioned behind home plate and responsible for receiving the pitch from the pitcher.

CATCHER’S BOX
Area behind home plate in which the catcher must stand until the pitcher delivers the ball.

CELLAR
A team in last place.

CHANGE UP
A slow-pitch thrown with the exact arm action as a fastball, designed to disrupt the timing of the hitter.

CHECKED SWING
A partial swing. If the swing has gone more than halfway around, the umpire can rule it a full swing, or strike.

CHEESE
A fastball.

CHIN MUSIC
A pitch that is high and inside.

CHOKE-UP (ON THE BAT)
Gripping the bat up on the handle away from the knob of the bat.

CIRCUS CATCH
An outstanding catch by a fielder.

CLEAN-UP HITTER
Player who hits fourth in the batting order.

CLOSER
Relief pitcher who specializes in pitching the last few outs of a game. Generally used to hold a lead in the late innings of a game.

COMPLETE GAME
Statistical credit to a starting pitcher for pitching the entire game.

COUNT
The number of called balls and strikes on a hitter.

CURVE
Pitch that moves down and across, because of the rotation of the ball.

CUTTER (CUT FASTBALL)
A fastball with a late break on it.

CYCLE
When a batter hits a single, double, triple and homerun in the same game.

DESIGNATED HITTER
Player who bats in the pitcher’s spot in the line-up. The DH does not have a fielding position.

DIAMOND
The infield playing surface.

DINGER
A homerun.

DONUT
Circular shaped weight that slides over the bat. The weight is used when a player is loosening up in the one deck circle.

DOUBLE
A hit that enables a batter to reach second base.

DOUBLEHEADER
Two games played back to back by the same teams.

DOUBLE PLAY
Any defensive play that results in two base runners being called out.

DUGOUT
Enclosed seating facility reserved for players, substitutes, coaches and other uniformed team members.

EARNED RUN
A run scored on a hit, walk or steal, without benefit from a defensive error on the play.

ERROR
Defensive mistake that allows a batter to stay at the plate or reach first base, or that advances a base runner.

FAST BALL
A straight pitch thrown by the pitcher as hard as possible.

FAIR TERRITORY
Part of the playing field within, and including the first base and third base lines, from home base to the bottom of the playing field fence and perpendicular upwards. All foul lines are in the fair territory.

FIELDER’S CHOICE
Term used when a fielder can chose among base runners or throw or tag out.

FIREMAN
A team's closing pitcher.

FLY BALL
Batted ball that goes high in the air.

FORCE OUT
An out created when a runner is forced to advance because there is another runner behind them, although they will be thrown or tagged out. The defensive player needs only to touch the base being approached by the runner with the ball in hand to record the out.

FORKBALL
A pitch thrown by placing the ball between the first two fingers, usually resulting in a sinking ball.

FOUL BALL
A ball that lands outside the first or third base foul lines.

FOUL LINE
Lines extending from home plate through 1st and 3rd base to the outfield fence and perpendicularly upwards. These lines are considered in play.

FOUL TERRITORY
Part of the playing field outside the first and third base lines extended to the fence and perpendicularly upwards.

GAP
The section of the outfield between the outfielders. Also called alley.

GRAND SLAM
A home run that is hit with a runner on every base. This hit scores 4 runs.

GREEN LIGHT
Signal from the coach to hit the next good pitch, or a signal to a base runner that gives the runner the authority to decide when to attempt a steal.

GROUNDER
A ground ball.

GROUND BALL
A ball hit in the infield by the batter that bounces in the infield.

HEAT (HEATER)
A fastball.

HIT
A play in which the batter safely reaches a base after hitting the ball, without aid from a fielding error or fielder’s choice.

HIT AND RUN
Play-action situation in which the batter must swing at the pitch while the base runner attempts to steal the base.

HOME PLATE
The fourth and final “station” to be reached by the runner. The offensive team is credited with one run every time a player safely crosses this base. A pitched ball must cross the plate when thrown by the pitchers to be credited as a strike on the batter.

HOT CORNER
Third base.

INFIELD
Area 90’ square with the corners being the four bases.

INFIELDER
Fielder who occupies a position in the infield. Most commonly refers to the first baseman, second baseman, third baseman, and shortstop.

INNING
A period of play. There are 9 innings in a regulation game, each team bats in an inning until they record 3 outs. The visiting team always bats in the top half (beginning) of an inning

INTENTIONAL WALK
Four balls thrown on purpose to a batter advancing the hitter to first base. Generally, executed when 1st base is empty to set-up a force play.

KNUCKLE BALL
A pitch thrown by gripping one of the seams on a ball with fingernails and/or knuckles of the forefinger and middle finger with the thumb another fingers underneath the ball. The ball is pushed out of the hand by the two fingers to keep the ball from rotating, causing the ball to move in an unpredictable manner.

LEFT ON BASE
Runners stranded on base after three outs.

LINE DRIVE
A ball hit in the air at a low projectory directly to a fielder or through the infield.

LINE-UP
A team’s batting order and fielding positions

MENDOZA LINE
A batting average of around .200. Named after Pirate shortstop Mario Mendoza.

MOUND
Hill the pitcher stands on while pitching.

NO HITTER
A game in which a pitcher does not allow the opposing team to reach a base via a safe hit.

ON DECK
A term used to refer to the next batter up in the inning. This person stands in a designated circular area and warms up before batting.

OUT IN ORDER
Retiring the first 3 batters in an inning.

OUTFIELD
Area between the back edge of the infield and home run fence.

OUTFIELDER
A fielder who occupies a position in the outfield, which is the playing field most distance from home base.

PASSED BALL
A pitched ball missed by the catcher, allowing a runner to advance.

PERFECT GAME
A game in which a pitcher does not allow any batter of the opposing team to reach base.

PICK OFF
An attempt by the pitcher to get a base runner out by throwing to the base from the stretch position.

PINCH HITTER
A hitter who substitutes in the line-up for a starting player. The original batter can’t return to the game, so the pinch hitter or a third person takes over the defensive position as well.

PINCH RUNNER
A player entering the game to run for someone already on base.

PITCHOUT
When a pitch is thrown wide of the strike zone on purpose. A catcher will signal for a pitchout if they think that a runner is trying to steal.

PITCHING ROTATION
The order in which the starting pitchers take turns starting games, usually with three or four days rest between starts.

PULL HITTER
A batter that generally hits to the same side of the field that he bats. (eg, righthanded pull hitter hits to the left side of the field).

PUTOUT
In scoring, a fielder is credited with a putout if he receives the ball to put out a base runner or a hitter.

QUALITY START
A start in which the pitcher pitches at least six innings and allows no more than three runs.

RELIEF PITCHER
The pitcher replacing the starting pitcher. The relief pitcher can win, lose, save, or not be involved in the game’s final score.

RUBBER
The pitching plate on the mound. The pitcher must have one foot connected to the plate while pitching to the batter. The rubber is located 60’ 6" (19.5 meters) from home plate.

RUN DOWN
A played used by fielders to tag out a runner caught between bases.

RUNNER
An offensive player who is advancing toward, touching, or returning to any base.

SACRIFICE BUNT
A bunt designed to advance a runner although the batter will be thrown out.

SACRIFICE FLY
Fly ball out that scores a runner from third base.

SAFE
Declaration by the umpire that a runner is entitled to the bases for which he was trying.

SCORING POSITION
Runner who is on second or third base.

SHORTSTOP
Defensive player positioned between second and third bases.

SHUT OUT
A game in which one team doesn’t score any runs.

SIGNS
Player signals given from the third base coach to the hitter and runner. Or, a hand signals given by the catcher to the pitcher suggesting the type of pitch to be thrown.

SINKER
A fast pitch that breaks downward as it reaches.

SLIDER
A pitcher that appears to the batter as a fastball until it reaches the plate, then breaks sharply on a level plane. The ball is held similarly to the curveball, but the wrist is kept straight, like a fastball, and broken downward.

SPIT BALL
Illegal pitch which a foreign substance (most commonly spit or grease) is applied to the ball causing it to react in an unpredictable manner.

STARTER
The pitcher who beings the game and pitches until he wins the game or is replaced by a relief pitcher.

STEAL
Attempting to advance a base between pitches without the batter hitting the ball or getting a base on balls.

STRIKE
A strike is called if a batter swings at a pitch and misses, or if the pitch simply passes through the strike zone. The first 2 foul balls that are not caught count as first and second strike. A foul ball that is not caught can never be counted as a third strike.

STRIKE ZONE
The area over home plate between the batter’s armpits and knees when the batter is positioned to swing. Any pitch that is delivered through this area is called a strike.

SUICIDE SQUEEZE PLAY
A play in which a runner on third breaks toward home on the pitch and the batter’s responsibility is to bunt the ball allowing the runner to score.

SWITCH-HITTER
Player who is able to bat left-handed or right-handed. A switch-hitter will bat from the opposite side in which the pitchers throws.

TAG
An action runners must perform before they can advance on a fly ball. Runners must touch the base they occupy after the ball is caught before they can try to advance. Runners can leave their base before a ball it hit, but must return and touch the base if the ball is caught. Or, an action executed when a defensive player touches a runner with the ball in an attempt to get them out.

TEXAS LEAGUER
A bloop hit that drops between the infielder and outfielder.

TOTAL PLATE APPEARANCES
Calculated for teams, leagues, and players by the following formula: TPA = AB + TBB + HBP + SH + SF.

TRIPLE
A hit enabling the batter to safely reach third base.

TRIPLE PLAY
A defensive play that records 3 outs.

TWO BASE HIT
A hit enabling the batter to safely reach second base. Also called a double.

UNCLE CHARLIE
A curve ball.

UTILITY PLAYER
A player who fills in at many different positions.

WALK
An award given to the batter after the pitcher delivers 4 balls. If a hitter receives 4 balls during an at bat, they automatically advance to first base. Any forced base runners also advance. Also called base on balls.

WHEELHOUSE
A hitters power zone.

WHIFF
A strike out.

WILD PITCH
A pitch so far from the strike zone that the catcher cannot catch or block it, permitting any base runner to advance a base.

Home