noun
police cell; lockup; drunk tank
Colloquial, slightly derogatory term for a police holding cell or temporary lockup. Often used in crime or yakuza contexts.
酔っ払ってブタ箱に入れられた。
I got drunk and thrown in the drunk tank.
あのチンピラはブタ箱に何度も入っている。
That punk has been in the lockup many times.
Compound of ブタ (pig) and 箱 (box), implying a cramped, dirty place like a pigsty. The exact origin is uncertain, but it likely arose as derogatory slang for police cells.