Ace: A team's best pitcher, usually the first pitcher in starting rotation.
Alley: Also called "gap"; the outfield area between the outfielders.
Around the Horn: A play run from third, to second, to first base.
Assist: An outfielder helps put an offensive player out, crediting the outfielder with an "assist".
At Bat: An offensive player is up to bat. The batter is allowed three outs.
Backdoor Slider: A pitch thought to be out of strike zone crosses the plate.
Backstop: The barrier behind the home plate.
Bag: The base.
Balk: An illegal motion made by the pitcher intended to deceive runners at base, to the runners' credit who then get to advance to the next base.
Ball: A call made by the umpire when a pitch goes outside the strike zone.
Ballist: A vintage baseball term for "ballplayer".
Baltimore Chop: A hitting technique used by batters during the "dead-ball" period and named after the Baltimore Orioles. The batter strikes the ball downward toward home plate, causing it to bounce off the ground and fly high enough for the batter to flee to first base.
Base Coach: A coach that stands on bases and signals the players.
Base Hit: A hit that reaches at least first base without error.
Base Line: A white chalk line drawn on the field to designate fair from foul territory.
Base on Balls: Also called "walk"; an advance awarded a batter against a pitcher. The batter is delivered four pitches declared "ball" by the umpire for going outside the strike zone. The batter gets to walk to first base.
Base-tender: A vintage baseball term referring to a baseman.
Base: One of four points on the baseball diamond that players must run through to reach the home plate.
Baseball: The official ball used in the sport of baseball.
Bases Empty: Bases contain no runners.
Bases Loaded: Bases contain runners.
Bat: Equipment the batter uses to strike the ball.
Batter: Offensive player in the batting box who will attempt to strike the ball.
Battery: A pitcher-catcher combination.
Batter's Box: Area next to home plate designated for the batter.
Batting Order: The official order, as determined by the umpire, of players who will step up to bat.
Behind: The catcher.
Bottom: The second half of the inning.
Box Score: Important inning information an official keeps track of by checking a series of boxes.
Breaking Ball: A curve ball that breaks speed.
Bronx Cheer: The sound of "boos" from the crowd during a game.
Brush-back: A pitched ball comes close to hitting the batter.
Bull Pen: Also called "the pen"; warm-up area for relief pitchers before entering the game.
Bunt: The ball is not swung at, but contacts the bat within the infield.
Called Game: The umpire temporarily stops the game.
Can of Corn: An easy fly-ball catch by an outfielder.
Catch: An outfielder captures the ball with his hand or glove.
Catcher: The player poised behind home plate to catch balls missed by the batter.
Catcher's Box: Space designated behind home plate for the catcher in between pitches.
Caught Looking: The batter does not swing at a pitch but a third strike is called.
Cellar: A team is in last place.
Change Up: A slow-ball pitch intended to deceive the batter into thinking it is a fastball.
Checked Swing: A swing by the pitcher that rotates halfway around or less.
Cheese: A great fastball pitch.
Chin Music: A pitch that comes close to a batter's face.
Choke-up: A batter grips the bat too far up from the knob.
Circus Catch: A great catch by an outfielder.
Clean-up Hitter: The fourth player up to bat.
Closer: Relief pitcher who finishes out the game.
Complete Game: The starting pitcher pitches the whole game.
Count: The total balls and strikes tallied on a batter.
Crank: An old-time term referring to a serious baseball fan.
Curveball: A pitch that angles to the left when delivered with the right hand, and visa versa.
Cutter: Also called "cut fastball"; a kind of fastball that breaks slightly before reaching home plate.
Cycle: Also called "natural cycle"; a batter achieves a single, double, triple, and a home run in one game.
Daisy Cutter: A vintage term for ground ball.
Dead: A ball that is out.
Defense: The team out on the field.
Designated Hitter: Non-field player designated to bat in the pitcher's position.
Diamond: The baseball field.
Donut: Circular weight attached to the bat and used in warm-up.
Double Header: A team plays two games in a row.
Double Play: A defense play resulting in two outs.
Double: A second-base hitter.
Dugout: Holding area for baseball officials and uniformed teammates not in play.
Earned Run: A home run scored with no errors against defense.
Error: A defense foul.
Fair Ball: A hit that stays within "fair territory".
Fair Territory: The field that is within playing boundaries.
Fast Ball: A ball pitched straight and fast.
Fielder: One of nine defensive team players.
Fielder's Choice: A fielder opts to throw the ball to a base other than the one the batter is running toward.
Fireman: The relief pitcher that closes out the game.
Fly Ball: A bat results in a high-flying ball.
Force Out: An out recorded when a runner is forced to advance to the next base because there is a runner behind him.
Force Play: A batter becomes a runner forcing a baseman to lose his position.
Forfeited Game: A game is ended and the opponent is awarded because of a foul committed by defense.
Fork Ball: A ball pitched between the index and middle fingers resulting in a slower, and often ground ball.
Foul Ball: A ball that settles outside the foul line.
Foul Line: Line drawn from home base through the first and third bases, and perpendicularly upward from the outfield fence.
Foul Territory: Area outside the foul line.
Foul Tick: An old-time term for foul ball.
Fungo Bat: A type of bat, generally thinner and longer, used to hit a fungo.
Fungo: A ball hit by a fungo bat to a fielder during practice.
Gap: Area between outfielders.
Gopher: A homerun hit.
Grand Slam: A homerun hit while all bases are loaded.
Green Light: The coach signals a good move to a batter or runner.
Ground Rule Double: A double base advance awarded runners on bases usually as a result of a batted ball bouncing off the ground and flying high over the wall or fence.
Grounder: Also called "ground ball", a hit that bounces off, or ends up rolling on, the infield.
Hit and Run: The players on base begin to run before the batter hits the ball.
Hit: The batter advances to a base without any field errors.
Home Plate: Home base where the batter takes a swing; the final point to be reached by runners on the course of four bases of the baseball diamond.
Home Point: A vintage term for home base.
Home Run: After striking the ball, the batter is able to pass through all four plates and return to home with no errors on the part of defense.
Home Team: The team whose field the game is being played on. If the field is neither team's, both will mutually decide which one to call home team.
Hot Corner: Third base.
Hurler: A vintage word for pitcher.
Huzzah!: An old-time baseball cheer from the crowd, meaning "Hurrah!" or "Hurray!"
Infield Fly: A fly ball in the infield that can easily be caught by an infielder.
Infield: The portion of the baseball field bordered by three bases and home plate.
Infielder: A player positioned on the infield.
Inning: One of nine periods of playtime in an ordinary regulation game.
Intentional Walk: A set-up for forced play in which the batter is delivered four pitches in order to advance to first base.
Knuckle Ball: A method of holding the ball with the knuckles in order to prevent a spin on the ball.
Left On Base: Three outs and bases are still loaded.
Leg it: Run!
Line Drive: A ball hit in a straight line directly to a fielder.
Line-up: A team's batting order.
Mascot: The batboy, in old-time baseball.
Mendoza Line: So-named after the legendary shortstop Mario Mendoza, and refers to having a batting average of around 200.
Mound: The pitching hill.
Muff: An error, in the early baseball era.
No Hitter: Also called "no-hit game" and "no-no"; refers to a game resulting in a team having no hits.
Offense: The team at bat.
On Deck: The next batter in the line-up.
Out In Order: The first three batters are called out in one inning.
Out: What the umpire calls when a batter or base runner for whatever reason cannot advance to the next base; such a player is said to be "retired".
Outfield: The area of the playing field that is outside the boundaries of the four-pointed baseball diamond.
Outfielder: A player in an outfield position.
Passed Ball: The ball escapes the catcher and runners get to advance to next base.
Perfect Game: The pitcher prevents every batter from the opposing team from getting to first base.
Pick Off: The pitcher throws the ball to a fielder who can then tag a base runner, preventing the runner from stealing or advancing to next base.
Pinch Hitter: A hitter replaces the starting player in the line-up.
Pinch Runner: A player replaces a runner already on base.
Pitch: Delivery of the baseball to the batter.
Pitcher: The offensive player that delivers the ball to the batter.
Pitching Rotation: The pitching order.
Pitchout: A deliberate wide pitch.
Pull Hitter: Hitting the ball toward the same side of the field from which he bats.
Putout: A fielder earns credit for receiving the ball to put out a base runner or hitter.
Quick Return Pitch: A pitch with intent to throw off the batter.
Relief Pitcher: The replacement for the starting pitcher.
Retire: The umpire calls an out, and a batter or base runner cannot advance to the next base.
Rubber: The pitching plate.
Run Batter In: Also known as "RBI", a record of points earned by a player for assisting his teammates in scoring points while up to bat.
Run Down: Fielders tag a runner between bases.
Run: A runner crosses home plate without any errors.
Runner: The player or batter advancing from one base to another.
Sacrifice Bunt: A bunt intended to advance a runner, to the batter's discredit.
Sacrifice Fly: A fly ball out and a runner scores a point.
Safe: Runner arrives safely at base, as called by the umpire.
Save: Credit given a relief pitcher for keeping the team in the lead despite that the opponent's tying or winning runs are on base, or if three or more innings are pitched without a tie game.
Scoring Position: Runner is on second or third base.
Scout: Vintage for outfielder.
Short Scout: Old-time term for shortstop.
Shortstop: Fielder positioned in between second and third bases.
Shut Out: A team fails to score any runs in a game.
Signs: Hand or body signals given by the coach or key players.
Single: A batter arrives safely to first base.
Sinker: A pitched fastball aimed downward.
Sky Ball: Vintage term for pop-up ball.
Slider: A pitch similar to a curveball but made with a straight wrist, resulting in what appears to be a fastball, but breaks when it reaches home plate.
Spit Ball: Unlawful pitch in which the ball is coated with saliva, grease, or other such substance, causing the ball to react unpredictably.
Starter: The pitcher who starts the game.
Steal: An offensive runner tries to advance to the next base during a pitch without the batter hitting the ball, or any assists.
Stolen Base: The recorded number of steals by a runner.
Strike Out: Three strikes by the batter.
Strike Zone: The area over home plate the ball must pass into to qualify as a strike.
Strike: A pitch is missed, or not swung at by the batter, and the ball crosses into the strike zone. Also, balls that foul but are not caught may qualify as first or second strike but not a third.
Striker: Vintage term for batter.
Suicide Squeeze: The batter bunts the ball attempting to throw first baseman off, but instead allows third base runner, as soon as the ball is pitched but released, to flee to home plate.
Switch-Hitter: A batter able to alternate batting with right or left hand.
Tag: A runner must touch his occupied base after the ball is caught, and before advancing to the next base. Also refers to a defense player who touches a runner with the ball in an effort to put them out.
Tater: Colloquial term for homerun.
Texas Leaguer: A hit that falls to the ground between the infielder and outfielder.
Throw: Different than a pitch; use of the hand to drive the ball toward a teammate or intended goal.
Top: First half of the inning.
Triple Play: Three players are taken out in the course of one play.
Triple: The batter makes it to third base without any errors or stopping.
Two-base Hit: Also called "double"; a batter is able to safely reach second base in one hit.
Umpire: The official person in charge of the game.
Uncle Charlie: Curve ball.
Utility Player: A person who can fill any position.
Walk: Also called "base on balls"; after four pitches are delivered the batter is allowed advance to first base, forcing other runners on base to advance as well.
Wheelhouse: A hitter's "sweet spot"; in other words their power zone.
Whiff: To strike out.
Wild Pitch: A pitch so wide that the catcher is unable to catch or block it, allowing runners to advance.