—n. (pl. -ies)
1 the product of eight and ten.
2 a symbol for this (80, lxxx, LXXX).
3 (in pl.) the numbers from
80 to 89, esp. the years of a century or of a person's life.
—adj. that amount to eighty.
Phrases and idioms:
eighty-first, -second , etc. the ordinal numbers between eightieth and ninetieth. eighty-one, -two , etc. the cardinal numbers between eighty and ninety.
Derivatives:
eightieth adj. & n. eightyfold adj. & adv.
Etymology: OE -eahtatig (as EIGHT, -TY(2))
Useful english dictionary. 2012.