Adar the king.
1) An idol; a form of the sun-god worshipped by the inhabitants of Sepharvaim (2 Kings 17:31), and brought by the Sepharvite colonists into Samaria.
2) A son of Sennacherib, king of Assyria (2 Kings 19:37; Isa. 37:38).
the cloak, glory, grandeur or power of the king ...
Hitchcock's Bible Names Dictionary
(splendor of the king). • The name of an idol introduced into Samaria by the colonists from Sepharv...
William Smith's Bible Dictionary