77 articles
3,000-hit club
The 3,000-hit club is the informal group of 33 MLB players with 3,000 career hits, from Cap Anson (1897) to Miguel Cabrera (2022); Pete Rose leads all players with 4,256 hits.
300 strikeout club
300 strikeout club: informal MLB group of pitchers with 300+ strikeouts in a season; 19 modern-era members in 38 instances; record 383 by Nolan Ryan (1973); Randy Johnson and Ryan lead with six seasons each.
500 home run club
The 500 home run club: 28 MLB players with 500+ career home runs, from Babe Ruth (1929) to Miguel Cabrera (2021); covers records, steroid-era prestige erosion, and Hall of Fame effects.
Armando Galarraga's near-perfect game
Armando Galarraga's near-perfect game: June 2, 2010 Tigers-Indians start in which umpire Jim Joyce's blown safe call at first base cost Galarraga the 21st MLB perfect game; officially a one-hit shutout.
Balk
Balk: an illegal, deceptive pitching motion in baseball with runners on base; runners advance one base. 13 listed acts, 1898 origin, 1988's 924-balk season, and MLB's 2023 two-disengagement limit.
Baseball (ball)
Baseball (ball): the regulated sphere of cork-and-rubber core, yarn windings, and stitched leather cover used in baseball; 5 to 5.25 oz, 9 to 9.25 inches, 108 stitches; MLB and NPB versions differ in seam height.
Baseball bat
Baseball bat: the batter's club, solid wood in MLB (max 2.61 in diameter, 42 in long), aluminum/composite elsewhere; BBCOR and USABat/USSSA standards, sweet spot physics, and 2025 torpedo bats.
Baseball field
Baseball field, or diamond: the playing area for baseball, with a fixed 90-foot square infield, 60 ft 6 in pitching distance, and variable outfield dimensions set by each ballpark.
Baseball glove
Baseball glove (mitt): padded leather or synthetic hand covering worn by fielders, first seen in the 1860s, patented from 1877, given its web pocket by Bill Doak in 1919, and modernized by Wilson's 1957 A2000.
Baseball positions
Baseball positions: the nine defensive spots (pitcher, catcher, infielders, outfielders) with scorebook numbers 1-9, positional difficulty order, 2023 shift restrictions, and the designated hitter role.
Baseball statistics
Baseball statistics: measurements of player and team performance, from Henry Chadwick's 1859 box score to batting average, OPS, ERA, sabermetrics, WAR (fWAR vs bWAR), and Statcast expected stats like xwOBA.
Baseball5
Baseball5 is the WBSC's five-inning, five-on-five urban variant of baseball and softball, played with a rubber ball and no bat, glove, or pitcher; Cuba holds both World Cup titles, and it debuts at Dakar 2026.
Batting average (baseball)
Batting average (AVG), baseball's hits divided by at-bats stat; excludes walks, HBP, sacrifices; batting title needs 502 PA; Cobb .366/.367 career, Duffy .438/.440 in 1894, last .400 was Williams .406 in 1941.
Batting order (baseball)
Batting order (baseball): the fixed nine-hitter sequence on the lineup card, its rulebook mechanics, traditional slot roles, sabermetric optimization worth 5-15 runs, protection theory, and MLB/NPB/youth differences.
Bill James
Bill James (born 1949), American baseball writer and statistician, father of sabermetrics; created Runs Created, Pythagorean expectation, and Win Shares; self-published the 1977 Baseball Abstract and advised the Boston Red Sox 2002–2019.
Breaking ball
Breaking ball: family of spun baseball pitches (curveball, slider, sweeper, slurve) that deviate from a straight path; usage shifted from curveballs (10.7% in 2019 to 8.5% in 2025) toward sliders and sweepers (22.6% in 2025).
Catcher
Catcher: baseball's defensive fielder crouched behind home plate who receives pitches, calls games via signals, blocks balls, frames pitches, and throws out stealers; wears mask, chest protector, shin guards, and padded mitt.
Corked bat
Corked bat: a wooden baseball bat hollowed out and filled with cork (also superballs, styrofoam) to reduce weight. Experiments show no trampoline effect and no added distance; MLB bans altered bats.
Curveball
Curveball: breaking baseball pitch with topspin and Magnus-force drop, slower than a slider; credited to Candy Cummings (1863), long debated by physicists, now declining in MLB usage.
Cut fastball
Cut fastball (cutter, FC): fastball variant with late glove-side break from an offset grip, opposite a two-seamer's run. Made famous by Mariano Rivera; now MLB's third most common pitch.
Dead-ball era
Dead-ball era: period of Major League Baseball, roughly 1901–1919, of dominant pitching and low scoring, ended in 1920 by Babe Ruth's home runs, the spitball ban, and the clean-ball policy after Ray Chapman's death.
Designated hitter
Designated hitter (DH), baseball rule letting a specialist bat for the pitcher; adopted by the AL in 1973 (Ron Blomberg first), universal in MLB since 2022, Central League Japan 2027.
Earned run average
Earned run average (ERA) is a baseball statistic measuring how many earned runs a pitcher allows per nine innings, credited to Henry Chadwick and officially adopted in 1912.
Eephus pitch
Eephus pitch (also spelled ephus): baseball's rarest, slowest pitch, a 45-55 mph high-arcing lob popularized by Rip Sewell after a 1941 hunting accident; named from Hebrew efes, 'nothing'; Ted Williams homered off it in the 1946 All-Star Game.
Extra innings
Extra innings: baseball innings after the ninth in tied games. In MLB regular-season play since 2020, each extra half-inning starts with an automatic runner on second (Rule 7.01(b)(2)), raising scoring and shortening games; variants exist in WBSC and WBC play.
Force play
A force play in baseball occurs when a runner must advance because the batter became a runner, and is out if the defense touches the next base first.
Foul ball
Foul ball: a batted ball outside fair territory in baseball. Dead ball, strike unless count has two strikes; foul tip caught by catcher stays live. Modern definition dates to 1920; foul-strike rule adopted 1901-03.
Four-seam fastball
Four-seam fastball (FF): baseball's fastest, straightest, most-used pitch, gripped across the seams with backspin. MLB average about 94 mph, roughly 2,260 rpm spin, 31.8% of 2024 pitches.
Glossary of baseball terms
Glossary of baseball terms: official rules vocabulary (strike zone, infield fly, fielder's choice), statistics (batting average, OPS+, wOBA, wRC+, save, blown save), and slang (walk-off, can of corn, southpaw), with origins and 2023-2025 rule and Statcast additions.
Grand slam (baseball)
Grand slam (baseball): a home run hit with the bases loaded, scoring four runs with four RBIs. First recorded by Roger Connor in 1881; career record 25 (Alex Rodriguez), single-season record six (Mattingly, Hafner).