Roundhouse

Part of speech: noun (n.)

1. A constable's prison; a lockup, watch-house, or station house. [Obs.]

2. A cabin or apartament on the after part of the quarter-deck, having the poop for its roof; -- sometimes called the coach.

3. A privy near the bow of the vessel.

4. A house for locomotive engines, built circularly around a turntable.