Meaning

noun a period during which something or somebody is dominant or powerful

noun the period during which a monarch is sovereign

noun royal authority; the dominion of a monarch

originFrom Middle English regnen, from Old French reignier, from the Latin verb rēgnō, and the noun rēgnum. Doublet of regnum. Displaced native Old English rīċe (“a reign”) and ricsian (“to reign”).

Etymology from Wiktionary, CC BY-SA 3.0