Easton's Bible Dictionary (1897)
One who has judicial authority, literally, a “lord of judgement;” a title given to the Persian governor of Samaria (Ezra 4:8, 9, 17).
Hastings' Dictionary of the Bible (1898) & Schaff's Bible Dictionary
CHAN'CELLOR . e. counsellor, royal prefect - the office held by Rehum, who was the Persian governor in Samaria at the time.