Easton's Bible Dictionary (1897)
Smooth-tongued, one of the chief priests in the time of Joiakim (Neh. 12:15).
Hastings' Dictionary of the Bible (1898) & Schaff's Bible Dictionary
HEL'KAI (whose portion is Jehovah), a priest in the days of Jehoiakim the high priest, Neh 12:15.
Hitchcock's Bible Names (1869)
same as Helek