1880s vs decade

1880s and decade both are nouns.

Word	Noun	Adjective	Verb	Adverb
1880s	Yes	No	No	No
decade	Yes	No	No	No

As nouns, decade is a hypernym of 1880s; that is, decade is a word with a broader meaning than 1880s:

Other hypernyms of 1880s include decennary, decennium.

1880s (noun)	decade (noun)
the decade from 1880 to 1889	the cardinal number that is the sum of nine and one; the base of the decimal system
	a period of 10 years