Definitions of regency:

noun: the office of a regent
noun: the period from 1811-1820 when the Prince of Wales was regent during George III's periods of insanity
noun: the period of time during which a regent governs
adjective: of or relating to or characteristic of the style (especially the style of furniture) favored during the Regency (1811-1820)
adjective: of or relating to a regency