Easton's Bible Dictionary (1897)
A confidential servant of the king (Gen. 37:36; 39:1). In Rom. 16:23 mention is made of “Erastus the chamberlain.” Here the word denotes the treasurer of the city, or the quaestor, as the Romans styled him. He is almost the only convert from the higher ranks of whom mention is made (comp. Acts 17:34). Blastus, Herod’s “chamberlain” (Acts 12:20), was his personal attendant or valet-de-chambre. The Hebrew word saris, thus translated in
Esther 1:10, 15; 2:3, 14, 21, etc., properly means an eunuch (as in the marg.), as it is rendered in Isa. 39:7; 56:3.
Smith's Bible Dictionary (1863)
an officer attached to the court of a king, who formerly had charge of the private apartments or chambers of the palace. He kept the accounts of the public revenues. The office held by Blastus, “the king’s chamberlain,” was entirely different from this. (Acts 12:20) It was a post of honor which involved great intimacy and influence with the king. For chamberlain as used in the Old Testament, see [Eunuch]
Hastings' Dictionary of the Bible (1898) & Schaff's Bible Dictionary
CHAM'BERLAIN. 2 Kgs 23:11. An officer who has charge of the royal chambers, or the king's lodgings, wardrobes, etc. In Eastern courts eunuchs were commonly employed for this service. Esth 1:10, Jud 4:12, 2 Sam 20:15. The word occurs twice in A.V. of N.T., but entirely different offices are meant in the Greek. Blastus, "the king's chamberlain," mentioned in Acts 12:20, "held a post of honor which involved great intimacy and influence with the
king." Erastus, "the chamberlain of the city of Corinth," who sent salutations to the Roman Christians, Rom 16:23, was probably the treasurer of the city.