מֶלֶכְ melek "king", used of Israelite kings (1:1, 7:1, 10, 13), foreign monarchs (1:15; 2:1) and of the kingship of gods (5:26).  It is interesting that despite the concentration on royalty in the oracles against the nations in 1:3-2:16, it is not till 1:15 that the word itself appears. Previously either the terms "the one enthroned" or "who grasps the scepter" were used.