Easton's Bible Dictionary (1897)
Brother of song = singer, the officer who was “over the household” of Solomon (1 Kings 4:6).
Smith's Bible Dictionary (1863)
the controller of Solomon’s household. (1 Kings 4:6)
Hastings' Dictionary of the Bible (1898) & Schaff's Bible Dictionary
AHI'SHAR (brother of the singer), the controller of Solomon's household. 1 Kgs 4:6.
Hitchcock's Bible Names (1869)
brother of a prince; brother of a song