The story
- Latin · derived fromdomus privata
- Anglo-Norman · derived fromprivé hostel
- English todayprivy house
From privy (“outhouse”) to clarify the intended sense, likely under the influence of Anglo-Norman privé hostel (attested in an 1139 British source) and Latin domus privata (1141).
Etymology from Wiktionary, CC BY-SA 4.0.