years vs eighties

years and eighties both are nouns.

Word	Noun	Adjective	Verb	Adverb
years	Yes	No	No	No
eighties	Yes	No	No	No

years (noun)	eighties (noun)
a late time of life	the time of life between 80 and 90
a prolonged period of time	the decade from 1980 to 1989
the time during which someone's life continues	the decade from 1880 to 1889