Webster’s Revised Unabridged Dictionary · 1913
Roundhouse
Round′house′ (·hous′), n. 1. A constable's prison; a lockup, watch-house, or station house. [Obs.]
2. (Naut.) (a) A cabin or apartament on the after part of the quarter-deck, having the poop for its roof; — sometimes called the coach. (b) A privy near the bow of the vessel.
3. A house for locomotive engines, built circularly around a turntable.