古英語の cyning, king, monarch, ruler からの略語で、原語ゲルマン語の *kuningaz, kin, family, race, clan, -ing, 集合名詞接尾辞に対応する。後に王、君主に使われる。派生的な意味として、鍵、重要な、大きな、などがある。皇帝との違いを比較する。
As leon is the king of bestes. [John Gower, "Confessio Amantis," 1390]In Old English, used for names of chiefs of Anglian and Saxon tribes or clans, then of the states they founded. Also extended to British and Danish chiefs they fought. The chess piece so called from early 15c.; the playing card from 1560s; use in checkers/draughts first recorded 1820. Applied in nature to species deemed remarkably big or dominant (such as king crab, 1690s). In marketing, king-size is from 1939, originally of cigarettes.
[I]t was [Eugene] Field who haunted the declining years of Creston Clarke with his review of that actor's Lear. ... Said he, "Mr. Clarke played the King all the evening as though under constant fear that someone else was about to play the Ace." ["Theatre Magazine," January 1922]