Citadel of GondorMinas Tirith in Gondor, but in fact strictly referring to the fortified seventh and highest circle of that city.
It was the city's strongest point, surrounded by high walls and battlements on the 'keel'. One reached the Citadel through the Seventh Gate, manned by the Guards of the Citadel.
The Citadel housed the Court of the Fountain, the Tower of Ecthelion and its court with the White Tree. There were also the King's House, lodgings for the Steward, Merethrond, barracks for the Guard, and other buildings for guests and other workers.