Eighties
来自Big Physics
Old English hunde(a)htatig, from hund (of uncertain origin) + e(a)hta ‘eight’ + -tig (see -ty2); the first element was lost early in the Middle English period.
etymonline
eighties (n.)
1827 as the years of someone's life between ages 80 and 89; from 1833 as the ninth decade of years in a given century; from 1854 with reference to Fahrenheit temperature. See eighty.
