Baseball Glossary
Learn the language of Baseball — answer-first definitions with real examples, beginner to pro.
37 terms
- Attack Angle (Batting)AdvancedAttack angle in batting is the vertical angle of the bat path through the hitting zone. A slightly upward attack angle (+5° to +15°) matches the pitch plane for hard contact.
- Backdoor Breaking BallAdvancedA backdoor breaking ball starts outside the strike zone, away from an opposite-handed batter, and breaks back over the outside corner for a called strike, appearing to be a ball until the last instant.
- BarrelAdvancedA barrel is a batted ball combining high exit velocity with an optimal launch angle at the same time. This means the exact combination most likely to produce extra-base hits.
- Barrel AccuracyAdvancedBarrel accuracy is how reliably a hitter makes contact on the sweet spot of the bat rather than the handle or end cap. This means a coaching-level read on contact-point precision, distinct from the formal "barrel" batted-ball classification.
- Called Strike RateAdvancedCalled strike rate is the percentage of pitches in the strike zone that a hitter takes for a strike rather than swinging at. This means the mirror image of chase rate, measuring missed opportunity rather than bad swings.
- Called-Strike-Plus-Whiff Rate (CSW%)AdvancedCSW% is a pitching metric that combines called strikes and swinging strikes (whiffs) as a share of total pitches thrown, measuring how often a pitcher generates a strike without the ball being put in play.
- Chase ContactAdvancedChase contact rate is the percentage of swings at pitches outside the strike zone that result in contact, measuring how well a hitter defends the plate even when they have made the decision to swing at a bad pitch.
- Collapsing Back SideAdvancedCollapsing the back side is a fault where the back knee and hip drop and buckle inward during the swing rather than staying stacked over the back foot, robbing the swing of ground force and forcing the arms to finish the job alone.
- Cut FastballAdvancedThe cutter is a fastball with late glove-side movement — harder than a slider, smaller break than a slider — that jams or cuts away from hitters.
- Diving Catch TechniqueAdvancedDiving catch technique is the mechanics of extending the body fully. This is parallel to the ground and glove-first, to catch a ball just beyond a fielder's normal running range. This means a last-resort option, not a first choice.
- Drag BuntAdvancedA drag bunt is a bunt initiated. At the same time, already moving toward first base. This means typically by a left-handed hitter using their momentum out of the box. This means designed to beat out a hit rather than sacrifice an out.
- Eephus PitchAdvancedThe eephus is a very slow, high-arcing pitch thrown with minimal arm speed. This means often 30-40 mph slower than a fastball. This means designed purely to disrupt a hitter's timing with an extreme change of pace.
- Effective VelocityAdvancedEffective velocity is the idea that a pitch's perceived speed to a hitter depends on its location. This means inside pitches feel faster, outside and low pitches feel slower. This means not just its radar-gun reading.
- Framing a PitchAdvancedFraming is a catcher's glove technique for receiving a borderline pitch in a way. This means soft hands, minimal extra movement, sticking the pitch where it arrives. This means that presents it favorably to the umpire as a strike.
- Front Door Breaking BallAdvancedA front door breaking ball starts inside on a same-handed batter. This means looking like it may hit them. This means and breaks back over the inside corner for a strike instead of a ball or hit-by-pitch.
- Ground Ball vs Fly Ball TendencyAdvancedGround ball versus fly ball tendency describes the overall shape of a hitter's batted-ball distribution. This means whether their typical attack angle produces mostly grounders, a balanced mix, or mostly fly balls. This means as a single profile rather than one isolated rate.
- Hard-Hit RateAdvancedHard-hit rate is the percentage of batted balls struck above a set exit-velocity threshold — typically 95 mph in MLB, scaled lower for amateur levels. It measures contact quality independent of luck.
- In-Between HopAdvancedThe in-between hop is the awkward bounce that reaches a fielder around shin or knee height. This means too high to pick off the dirt, too low to receive comfortably out front. A common source of errors on routine-looking ground balls.
- Knuckle CurveAdvancedA knuckle curve is a curveball variation gripped with one finger (usually the index) bent and pressed knuckle-first against the ball, instead of laid flat. This produces a tighter spin axis and a later, sharper break.
- On-Plane SwingAdvancedAn on-plane swing travels along the incoming pitch's flight path through the hitting zone. This keeps the barrel and ball aligned for a longer window and converting timing errors into contact rather than misses.
- Pitch SequencingAdvancedPitch sequencing is the art of ordering pitches to exploit a hitter's tendencies and set up future offerings. This means making each pitch more effective. This is because of what came before.
- Pitch TunnelingAdvancedPitch tunneling is the strategy of throwing different pitch types that share the same flight path early before diverging late. This means making it nearly impossible for the hitter to distinguish them in time.
- Pitching DeceptionAdvancedPitching deception refers to any element of a pitcher's mechanics, grip, or delivery that delays or confuses the hitter's ability to identify the pitch type, speed, or location.
- Pop Time (Catcher)AdvancedPop time is the total time from a pitch hitting the catcher's mitt to the ball arriving in the fielder's glove at second base on a stolen-base or steal attempt, measured in seconds.
- Quick PitchAdvancedA quick pitch is a pitcher delivering the ball before the batter is set and ready in the box. This means an attempt to catch the hitter off guard that is illegal at most levels of play.
- Range FactorAdvancedRange factor is a traditional defensive statistic calculated as putouts plus assists per game (or per nine innings). It is used as a rough proxy for how much ground a fielder covers.
- Reading the Ball off the BatAdvancedReading the ball off the bat means recognizing a batted ball's trajectory, speed, and likely landing spot in the split-second after contact. This uses bat angle and initial ball flight rather than waiting to track its full arc.
- Spin Rate (Pitching)AdvancedSpin rate is how fast the ball rotates in revolutions per minute (RPM) after leaving the hand. This means higher spin amplifies the Magnus effect and increases pitch movement.
- Splitter / ForkballAdvancedThe splitter is an off-speed pitch gripped with the fingers spread across the seams. This produces late diving action that generates weak contact or swings below the zone.
- Squared-Up RateAdvancedSquared-up rate measures how close a batted ball's exit velocity comes to the maximum possible speed the bat and pitch could theoretically produce on that particular swing. This means a measure of contact-point precision independent of raw bat speed.
- Squeeze Play (Bunt)AdvancedA squeeze play is a bunt called in particular to score a runner from third base. This means a "suicide squeeze" sends the runner as the pitch is thrown regardless of where the bunt goes. At the same time, a "safety squeeze" holds the runner until the bunt is down.
- Swing LengthAdvancedSwing length is the total distance the bat's barrel travels from the start of the swing to contact. This means a shorter, more direct path generally means less time is needed to react, at some cost to the maximum bat speed a longer path can generate.
- Time to ContactAdvancedTime to contact is how long, in fractions of a second, it takes a hitter's swing to travel from its trigger to the ball. This means the metric that ultimately determines how late a hitter can afford to start their swing against a given velocity.
- Tools Grade Scale (20-80)AdvancedThe 20-80 scale is the standard scouting numbering system used to grade each of a player's tools, where 50 represents a Major League average, 80 is elite, and 20 is well below usable at the highest level.
- Tunnel PointAdvancedThe tunnel point is the point in a pitch's flight. This means roughly where the batter must decide to swing. This means where two different pitch types are still on nearly identical trajectories before diverging.
- Weighted On-Base Average (wOBA)AdvancedWeighted On-Base Average (wOBA) gives each hitting outcome a run value. It combines walks and hits into one rate that is scaled like on-base percentage.
- Zone Contact RateAdvancedZone contact rate is the percentage of swings at pitches inside the strike zone that result in contact. This means a core measure of basic bat-to-ball ability on pitches a hitter should be equipped to handle.
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