Reign (rn), v. i. [imp. & p. p. Reigned (rnd); p. pr. & vb. n. Reigning.]
Etymology: [OE. regnen, reinen, OF. regner, F. régner, fr. L. regnare, fr. regnum. See Reign, n.]
1. To possess or exercise sovereign power or authority; to exercise government, as a king or emperor;; to hold supreme power; to rule. Chaucer. We will not have this man to reign over us. Luke xix. 14. Shall Banquo's issue ever Reign in this kingdom Shak.
2. Hence, to be predominant; to prevail. "Pestilent diseases which commonly reign in summer." Bacon.
3. To have superior or uncontrolled dominion; to rule. Let not sin therefore reign in your mortal body. Rom. vi. 12.
Syn. -- To rule; govern; direct; control; prevail.
1 other Webster entry under this spelling
Reign (rn), n.
1. Royal authority; supreme power; sovereignty; rule; dominion. He who like a father held his reign. Pope. Saturn's sons received the threefold reign Of heaven, of ocean,, and deep hell beneath. Prior.
2. The territory or sphere which is reigned over; kingdom; empire; realm; dominion. [Obs.] Spenser. [God] him bereft the regne that he had. Chaucer.
3. The time during which a king, queen, or emperor possesses the supreme authority; as, it happened in the reign of Elizabeth.
Shades of meaning
Fernald has no entry of its own for reign; he lists it under govern.
Where he writes about it:
The word reign, once so absolute, now simply denotes that one holds the official station of sovereign in a monarchy, with or without effective power; the Queen of England reigns; the Czar of Russia both reigns and rules. — from govern