Thayer's Greek Lexicon

 1. "head-quarters" in a Roman camp, the tent of the commander-in-chief
2. the palace in which the governor or procurator of a province
resided, to which use the Romans were accustomed to appropriate
the palaces already existing, and formerly dwelt in by kings or
princes; at Jerusalem it was a magnificent palace which Herod the
Great had built for himself, and which the Roman procurators
seemed to have occupied whenever they came from Caesarea to
Jerusalem to transact public business
3. the camp of the Praetorian soldiers established by Tiberius