What is the diamond in Baseball?

Section 3: Playing Area

Base paths: 90 feet (27.43 m) between bases.
Pitching distance: 60 feet 6 inches (18.44 m) from the front edge of the pitcher's plate to the back point of home plate.
The mound: A raised circle of dirt with the pitcher's plate set 10 inches (25.4 cm) above the level of home plate, sloping down toward the plate.
Home plate: A five-sided rubber plate, with a batter's box marked on each side.

Foul lines: Extend from the back point of home plate through the outside edges of first and third base to the outfield fence; foul poles mark where the lines meet the fence.
Running lane: A marked lane in foul territory along the last portion of the base path to first base, within which the batter-runner must run to avoid interference.
On-deck circles and coaches' boxes: Marked areas for the next batter and for the first- and third-base coaches.

The outfield extends from the infield to the home-run fence. The rules book sets recommended minimum fence distances — on the order of 330 feet down the lines and 400 feet to center field for new and renovated fields.
A warning track, where present, alerts outfielders as they approach the fence.

Dugouts / team areas: Enclosed and, where possible, screened for protection from foul balls and thrown bats.
Bullpens: Areas where relief pitchers warm up.
Spectator areas behind home plate and along the lines are protected by netting and barriers.

Base paths: 90 feet (27.43 m) between bases.
Pitching distance: 60 feet 6 inches (18.44 m) from the front edge of the pitcher's plate to the back point of home plate.
The mound: A raised circle of dirt with the pitcher's plate set 10 inches (25.4 cm) above the level of home plate, sloping down toward the plate.
Home plate: A five-sided rubber plate, with a batter's box marked on each side.

Foul lines: Extend from the back point of home plate through the outside edges of first and third base to the outfield fence; foul poles mark where the lines meet the fence.
Running lane: A marked lane in foul territory along the last portion of the base path to first base, within which the batter-runner must run to avoid interference.
On-deck circles and coaches' boxes: Marked areas for the next batter and for the first- and third-base coaches.

The outfield extends from the infield to the home-run fence. The rules book sets recommended minimum fence distances — on the order of 330 feet down the lines and 400 feet to center field for new and renovated fields.
A warning track, where present, alerts outfielders as they approach the fence.

Dugouts / team areas: Enclosed and, where possible, screened for protection from foul balls and thrown bats.
Bullpens: Areas where relief pitchers warm up.
Spectator areas behind home plate and along the lines are protected by netting and barriers.