At ’em ball — A ball hit right at a defensive player.

Baltimore Chop — A ground ball that hits in front of home plate (or off of it) and takes a large hop over the infielder’s head.

Bases drunk — Bases loaded.

Bazooka — Strong throwing arm. “He’s got a bazooka.”

Big show — The major leagues.

Bush league — Lesser minor-league teams in small cities or towns.

Catch napping — To surprise a less than alert runner with the result that he is picked off or suddenly caught between bases.

Chin music — A beanball or knockdown pitch that passes close to the batter’s jaw.

Circus catch — A spectacular catch, suggesting the moves of a circus acrobat.

Crackerjack — Term used to describe a first-rate or spectacular player or team.

Curtain call — The practice of a player coming out of the dugout to acknowledge the call of the fans, usually after a home run.

Deuce — The curveball, usually signaled from a catcher to a pitcher by holding down two fingers.

Dying quail — A batted ball that drops suddenly and unexpectedly, like a bird that has been shot on the wing.

Fence buster — A heavy hitter.

Free pass — Base on balls.

Friendly confines — Descriptive of many home ballparks, but most often used to describe Wrigley Field.

Glass arm — A sore throwing or pitching arm.

Golden Sombrero — A batter who strikes out four times in the same game is said to wear the golden sombrero.

Goose egg — A zero on the scoreboard.

Gopher ball — A pitch destined to be hit for a home run; one that will “go for” a run.

Guess hitter — Batter who tries to anticipate or out-guess the pitcher based on the situation at hand.

“Hit ’em where they ain’t” — Rallying cry for batters through the decades since 1897, when Wee Willie Keeler hit .432. Asked how a man of his size could put together such an average, Keeler responded: “Simple. I keep my eyes clear and I hit ’em where they ain’t.”

Hot stove league — Term for the gab, gossip and debate that takes place during the winter months when baseball is idle.

Iron glove — Sloppy fielding; prone to errors.

Lollipop — A soft pitch or weak throw.

Mendoza line — Figurative boundary in the batting averages between those batters hitting above and below .215, Mario Mendoza’s career average.

Picasso — A control pitcher; one who paints the black.

Platter — Home plate.

Play by the book — To play in accord with the conventional wisdom of the game.

Pow wow — A meeting on the playing field, usually involving several players and a coach who has come on to the field to talk strategy.

Punch-and-Judy — Said of a hitter who tends to hit well-placed but weakly-hit balls for singles. The first reference was made by former Los Angeles Dodgers manager Walter Alston when asked about a home run by Willie McCovey of the San Francisco Giants. “When he belts a home run, he does it with such authority it seems like an act of God. You can’t cry about it. He’s not a Punch and Judy belter.”

Rhubarb — A ruckus with the umpires; confusion; a fight between players.

Right down Broadway — A pitch that is delivered in the middle of the strike zone.

Room service — Term describing a pitch or batted ball that comes right to a defensive player.

Shoestring catch — A catch made by a running fielder just before the ball hits the ground.

Texas Leaguer — A poorly hit ball that loops meekly over the infield and lands for a hit.

The Show — The major leagues

Tools of ignorance — The catcher’s paraphernalia: shin guards, chest protector, helmet, mask and glove.

Twin killing — Double play.

Warning track power — The ability of a batter with enough strength to hit a ball to the warning track, but not enough to hit a home run.

Whiff — For a pitcher to strike out a batter.

Whitewash — To shut out a team.

Worm burner — Batted ball that moves across the ground hard and fast.

Source:Dickinson’s Baseball Dictionary