bullpen

noun

bull·​pen ˈbu̇l-ˌpen 

also ˈbəl-

variants or less commonly bull pen

plural bullpens also bull pens

1

: a large cell where prisoners are detained until brought into court

Commonly called the "bullpen," the court lockup is behind the courtroom and is used as a holding area for prisoners …

—Bruce A. Scruton

2

a

: a place on a baseball field where pitchers warm up before they start pitching

In the bullpen, Goose Gossage is warming up.

—Tony Scherman

b

: the relief pitchers of a baseball team

After five innings Seattle led 14-2 and, with baseball's best bullpen waiting to protect the lead should starter Aaron Sele falter …

—Sports Illustrated

3

: an open work area not divided into offices

… an alternative to the traditional combination of private offices for the brass and bullpens for the workers.

—Carl Ruff

Examples of bullpen in a Sentence

Recent Examples on the Web

The Royals bullpen is projected to be a strength with the veteran arms available. —Jaylon Thompson, Kansas City Star, 9 Jan. 2026

Up — Acquired to serve as a set-up man in 2024, Peralta finished that year in the shadow of the likes of Robert Suarez, Jason Adam and Tanner Scott and remained in middle relief to start 2025 even before the team acquired Mason Miller to fortify the bullpen. —Jeff Sanders, San Diego Union-Tribune, 9 Jan. 2026

But Doval, 23, was a 2023 All-Star and is expected to be a key part of the Yankees’ bullpen this year. —Peter Sblendorio, New York Daily News, 9 Jan. 2026

But more likely, the team will focus on supplementing its bullpen and adding a right-handed-hitting first baseman. —Maria Torres, New York Times, 9 Jan. 2026

In the deciding Game 4, Luzardo came out of the bullpen to throw 1 2/3 innings, striking out three batters and allowing two hits and an unearned run. —Tom Dougherty, CBS News, 8 Jan. 2026

Watson and Samaniego are both relievers who have never appeared in the majors but who are expected to compete for spots in Boston’s bullpen. —Mac Cerullo, Boston Herald, 8 Jan. 2026

Minasian said the Giants may use their young starters (Hayden Birdsong, Blade Tidwell, Carson Whisenhunt, Trevor McDonald and Kai-Wei Teng) out of the bullpen but added there will be opportunities to start since no rotation survives an entire year with just five pitchers. —Justice Delos Santos, Mercury News, 6 Jan. 2026

Word History

First Known Use

1809, in the meaning defined at sense 1

Rhymes for bullpen

• again
• airmen
• amen
• culmen
• flagmen
• gunmen
• lawmen
• oilmen
• playpen
• schoolmen
• tegmen
• ben

Kids Definition

bull pen

noun

1

: a large cell where prisoners are held until brought into court

2

a

: a place on a baseball field where relief pitchers warm up

b

: the relief pitchers of a team