From BiblePortal Wikipedia

Hastings' Dictionary of the New Testament [1]

The only person clearly designated as such in the NT is Blastus, ὁ ἐπὶ τοῦ κοιτῶνος τοῦ βασιλέως ( sc . Herod Agrippa i.), whom the Tyrians and Sidonians persuaded to befriend them against the king’s displeasure at Caesarea, and to obtain peace for them ‘because their country was nourished by the king’s country’ ( Acts 12:20). The office he held would obviously involve great intimacy and influence with the king. Erastus, who is called ‘the chamberlain of the city’ in  Romans 16:23 (Authorized Version; Revised Version‘treasurer’), held a different office (see Steward). The eunuch of  Acts 8:27 ff. also held a different office he ‘was over all’ the queen’s ‘treasure’ (see Ethiopian Eunuch).

C. L. Feltoe.

Vine's Expository Dictionary of NT Words [2]

1: Ἐπί (Strong'S #1909 2849 — Preposition — ho epi tou koitonos — ep-ee' )

lit., "the (one) over the bedchamber" (epi, "over," koiton, "a bedchamber"), denotes "a chamberlain," an officer who had various duties in the houses of kings and nobles. The importance of the position is indicated by the fact that the people of Tyre and Sidon sought the favor of Herod Agrippa through the mediation of Blastus,  Acts 12:20 .

 Romans 16:23

Hastings' Dictionary of the Bible [3]

Chamberlain . In OT the word occurs in   2 Kings 23:11 and repeatedly in Est., where the original is ‘eunuch’ ( sârîs ); but it is generally believed that this name is not to be taken always in a literal sense, and hence it is often rendered by the word ‘officer.’ In Esther, however, the chamberlain evidently belongs to that class of persons who are entrusted with the watchful care of the harems of Oriental monarchs. In NT at   Acts 12:20 it is said that the people of Tyre and Sidon sought the favour of Herod Agrippa through the mediation of Blastus ‘the king’s chamberlain,’ showing that the office was one of considerable influence. The word occurs again in AV [Note: Authorized Version.] in   Romans 16:23 , but is rendered in RV [Note: Revised Version.] more accurately ‘treasurer of the city.’

People's Dictionary of the Bible [4]

Chamberlain.  2 Kings 23:11. An officer who had charge of the royal chambers, or the king's lodgings, wardrobes, etc.  Esther 1:10;  Esther 1:12;  Esther 1:15 A. V. The R. V. reads "chamberlains," but has "or eunuchs" in the margin. 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,"  Romans 16:23, was the treasurer of the city; the R. V. reads "treasurer."

Holman Bible Dictionary [5]

saris  2 Kings 18:17  Jeremiah 39:3 Daniel 1:3 saris   Genesis 37:36 Genesis 40:7 Esther 1:10  2 Kings 9:32 1 Samuel 8:15 1 Kings 22:9 2 Kings 8:6 2 Kings 23:11 2 Kings 24:15 2 Kings 25:19Eunuch

Smith's Bible Dictionary [6]

Chamberlain. 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 .

Fausset's Bible Dictionary [7]

 Romans 16:23; Erastus, Oikonomos , steward or public treasurer of the city, who kept account of the revenues. Latin Arcarius . So in inscriptions in Marm. Oxon., 85, Neilos is called oikonomos of Asia. On the other hand Blastus was chamberlain ( Epi Tou Koitonos Tou Basileos ) in a different sense, namely, over the king's bedchamber, a post of honor and intimacy ( Acts 12:20).

Webster's Dictionary [8]

(1): (n.) An upper servant of an inn.

(2): (n.) An officer having the direction and management of the private chambers of a nobleman or monarch; hence, in Europe, one of the high officers of a court.

(3): (n.) An officer or servant who has charge of a chamber or chambers.

(4): (n.) A treasurer or receiver of public money; as, the chamberlain of London, of North Wales, etc.

Easton's Bible Dictionary [9]

 Genesis 37:36 39:1 Romans 16:23  Acts 17:34 Acts 12:20 Saris   Esther 1:10,15 2:3,14,21 Isaiah 39:7 56:3

Morrish Bible Dictionary [10]

1. Eunuch who had care of the king's wives and concubines.  2 Kings 23:11;  Esther 1:10-15;  Acts 12:20 .

2. Chamberlain, i.e., the treasurer or steward of the City of Corinth, whose salutations Paul sent to Rome.   Romans 16:23 .

American Tract Society Bible Dictionary [11]

 2 Kings 23:11 , An officer who had charge of a king's lodgings and wardrobe. In eastern courts eunuchs were generally employed in this office,  Esther 1:1-22,10,12,15 . This title in  Romans 16:23 probably denotes the steward or treasurer of the city.

Cyclopedia of Biblical, Theological and Ecclesiastical Literature [12]

( סָרַיס , Saris',  2 Kings 23:18;  Esther 1:10;  Esther 1:12;  Esther 1:14;  Esther 2:3;  Esther 2:14-15;  Esther 2:21;  Esther 4:4-5;  Esther 6:2;  Esther 6:14; Sept. regularly Εὐνοῦχος , twice Σπάδων , all signifying Castrated; in other places it is translated "eunuch," or "officer"). The term appears to have been applied to officers confidentially employed about the person of the sovereign; thus Potiphar, who was also captain of the guard, in the Egyptian court, is styled thus ( Genesis 37:36;  Genesis 39:1). It probably also occurs in the title Rab Saris (q.v.). The title "chamberlain" ( Οἰκονόμος ) , in  Romans 16:23, probably denotes the steward or treasurer of the city, called by the Romans the Quaestor. The Vulg. renders it by Arcarius, which was the title of a class of inferior magistrates, who had the charge of the public chest (Area Publica), and were under the authority of the senate. They kept the accounts of the public revenues. (See Reinesius, Syntagm. Inscr. p. 431; La Cerda, Advers. Sacr. cap. 56; Elsner, Obs. Sacs. 2, p. 68; and a note by Reinesius to the MAarmora Oxoniessia,' p. 515, ed. 1732.) Blastus is said in  Acts 12:20, to have been "the king's (Herod's) chamberlain" ( Ἐπι Τοῦ Κοιτῶνος Τοῦ Βασιλέως ) , by which is probably meant his personal attendant or valet de chambre. It was a post of honor, which involved great intimacy and influence with the king. The margin of our version gives "that was over the king's bedchamber," the office thus corresponding to that of the praefectus cubiculo (Suetonius, Dom. 16). (See Eunuch).

in a monastery, was overseer of the dormitory, and purchased clothes, bed furniture, and other necessaries. He received all considerable sums of money or other dues. He acted as treasurer, having the charge of nearly every considerable payment. At Durham his exchequer was near the abbey gates, under which was the tailors shop for making linsey-woolsey shirts and tunics for the monks and novices, and whole and half socks of white woolen cloth. At Abington his chamber was in the dormitory. He provided copes, albs, cowls, coverlets, hoods, shoes and boots, towels, combs, knives, beds, straw pelisses, stools, bed-perches, hot water, tools for the tailors and cordwainers, five lights burning in the dormitory from twilight to dawn, and baths three times a year. At Canterbury he provided mats, blankets, razors, all the monks' clothing, horseshoes for the farriers, and glass for the dormitory. The old clothing was distributed by him to the poor. Under him were the laundry folk, peltmen, or skin dressers, tailors, shoemakers, etc. In a cathedral he was often called the provost, and, like the massarius in Italy chamarier of Lyons, Strasburg, and Saragossa, was the receiver of rents and paymaster of the stipends and money for pittances, and general accountant of income and keeper of the common chest. He was annually elected, and took precedence of canons while in office. At St. Paul's he found the necessaries for divine service and posted the summonses of prebendaries to chapter on their stalls, and at York acted as punctator of the absences of the vicars. In the latter instance he might be a vicar.

International Standard Bible Encyclopedia [13]

chām´bẽr - lin  : In the Old Testament the word rendered chamberlain, סריס , ṣārı̄ṣ , is more properly "eunuch," an officer which oriental monarchs placed over their harems ( Esther 1:10 ,  Esther 1:12 ,  Esther 1:15;  Esther 2:3 ,  Esther 2:14 ,  Esther 2:21;  Esther 4:4 f;   Esther 6:2 ,  Esther 6:14;  Esther 7:9;  2 Kings 23:11 ). This officer seems also to have had other duties. See under Eunuch . In the New Testament (1) οἰκονόμος , oikonómos , literally manager of the household, apparently the "treasurer" as in the Revised Version (British and American) "Erastus the treasurer of the city saluteth you" ( Romans 16:23 ). Compare adapted use as applied to Christian apostles and teachers, bishops, and even to individual members; in which cases, rendered "stewards" ( 1 Corinthians 4:1;  Titus 1:7;  1 Peter 4:10 ). (2) In  Acts 12:20 , "Blastus the king's chamberlain" ( ho epı́ toú koitō̇nos toú basiléōs , "he who is over the king's bed-chamber"), not treasure-chamber, as above; here praefectus cubiculo , or chief valet de chambre to the royal person, a position involving much honor and intimacy.