alley — the section of the outfield between the outfielders. Also 'gap'.

around the horn — a double play going from third base to second to first

bag — a base

Baltimore chop — a ground ball that lands in front of home plate and takes a large hop over the infielder's head

bang-bang play — a play in which the base-runner hits the bag a split-second before the ball arrives or vice versa

Bronx cheer — when the crowd boos

can of corn — an easy catch by a fielder

cellar — last place. Also 'basement'.

fungo — a ball hit to a fielder during practice, usually with a fungo bat which is longer and thinner than a normal bat

hot corner — third base

rhubarb — a fight or scuffle

seeing-eye single — a soft ground ball that finds its way between the infielders for a base hit

shoestring catch — a running catch made just above the fielder's shoes

Texas Leaguer — a bloop hit that drops between an infielder and outfielder

tools of ignorance — catcher's equipment

twin killing — a double play

wheels — a ballplayer's legs

backdoor slider — a pitch that appears to be out of the strike zone, but then breaks back over the plate

brushback — a pitch that nearly hits a batter

cheese — describes a good fastball. Also 'good cheese'.

chin music — a pitch that is high and inside, sometimes designed to deliberately intimidate the batter

closer — a team's relief pitcher who finishes the game

cutter — a cut fastball which breaks late

fireman — a team's closer or late-inning relief pitcher

hill — the pitcher's mound

meatball — an easy pitch to hit, usually right down the middle of the plate

painting the black — when a pitcher throws the ball over the edge of the plate

punchout — a strikeout

set-up man — a relief pitcher who usually enters the game in the 7th or 8th inning

southpaw — a left-handed pitcher

Uncle Charlie — a curve ball

whiff — a strikeout

yakker — a curve ball

bandbox — a small ballpark that favours hitters

caught looking — when a batter is called out on strikes

cycle — when a batter hits a single, double, triple and home run in the same game

gopher ball — a pitch hit for a home run, as in 'go for'.

in the hold — the batter who is next up to the plate

on the screws — when a batter hits the ball hard. Also 'on the button'.

rope — a hard line drive. Also 'frozen rope'.

Ruthian — with great power, as in Babe

table setter — a batter whose job is to get on base for other hitters to drive him in. Usually a leadoff or second hitter.