Regency era vs Regency

Regency era and Regency both are nouns.

Word	Noun	Adjective	Verb	Adverb
Regency era	Yes	No	No	No
Regency	Yes	No	No	No

As nouns, Regency era and Regency are synonyms defined as:

Regency era and Regency: the period from 1811-1820 when the Prince of Wales was regent during George III's periods of insanity

Regency era (noun)	Regency (noun)
the period from 1811-1820 when the Prince of Wales was regent during George III's periods of insanity	the period from 1811-1820 when the Prince of Wales was regent during George III's periods of insanity