'Citadel' in the Bible

When he came to the citadel, he took them from their hand and put them in the house, then sent away the men so that they went.

It happened that when he finished offering the burnt offering, Jehu said to the royal guard and to the officers, "Come and kill them; let no man go free!" So {they put them to the sword}, and the royal guard and the officers threw them out, then they went up to the citadel of the temple of Baal.

Pekah the son of Remaliah, his captain, conspired against him, so he attacked him in Samaria in the citadel fortress of [the] palace of the king, with Argob and Arieh. With him [also were] fifty men from the children of the Gileadites, and he killed him and became king in his place.