also: とらばこ
noun
drunk tank; cell for holding drunks
Slang term for a police holding cell where intoxicated people are temporarily detained.
酔っ払ってトラ箱に入れられた。
I got drunk and was thrown in the drunk tank.
留置場 is the formal term for a police detention cell, while トラ箱 is slang specifically for a drunk tank.
Compound of トラ (tora, 'tiger') and 箱 (hako, 'box'). The exact origin is uncertain, but it likely refers to the rowdy, tiger-like behavior of intoxicated detainees or the cage-like nature of the holding cell.