noun
one's 80s; eighties
Refers to the age range 80–89, or to a person in that age range. Often used with possessive or descriptive phrases.
祖父は８０代ですが、まだ元気です。
My grandfather is in his eighties, but he is still healthy.
８０代の人口が増えている。
The population of people in their eighties is increasing.
Compound of 八十 (eighty) and 代 (generation, age range).