noun
age eighty; one's eighties
Refers to the age of eighty or the decade of one's eighties. Often used in contexts like birthdays, longevity celebrations, or describing someone's age.
祖母は今年で八十路を迎えます。
My grandmother will turn eighty this year.
八十路になっても毎日散歩を続けている。
Even in his eighties, he continues to take a walk every day.
米寿 is the celebration of one's 88th birthday, a specific milestone, whereas 八十路 simply denotes the age of eighty or the eighties.
八十 (eighty) + 路 (suffix indicating a decade of age). The suffix 路 is used in words like 四十路 (forties), 五十路 (fifties), etc., to denote a range of ages.