|Easton's Bible Dictionary|
Chamberlain to king Herod Agrippa I. (Acts 12:20). Such persons generally had great influence with their masters.
Int. Standard Bible Encyclopedia
blas'-tus (Blastos, "shoot"): The chamberlain of Herod Agrippa I, whose services as an intermediary between them and the king were gained by the people of Tyre and Sidon. These cities were dependent on Palestine for corn and other provisions, and when Herod, on the occasion of some commercial dispute, forbade the export of foodstuffs to Tyre and Sidon, they were at his mercy and were compelled to ask for peace. "Having made Blastus the king's chamberlain their friend," probably by means of a bribe, the Phoenician embassy was given an opportunity of setting their case before Herod (Acts 12:20).
S. F. Hunter
Blastus (1 Occurrence)
Acts 12:20 Now Herod was very angry with the people of Tyre and Sidon. They came with one accord to him, and, having made Blastus, the king's personal aide, their friend, they asked for peace, because their country depended on the king's country for food. (WEB KJV WEY ASV BBE DBY WBS YLT NAS RSV NIV)