- 1
An enclosure (enclosed area) used to contain domesticated animals, especially sheep or cattle.
- There are two steers in the third pen.
- 2
A penitentiary, i.e. a state or federal prison for convicted felons.slang
- They caught him with a stolen horse, and he wound up in the pen again.
- 3
The bullpen.
- Two righties are up in the pen.
syn. biro · pen