eighty

UK: /ˈeɪti/ US: /ˈeɪti/ ,(ā′tē)

Inflections of 'eighty' (n): npl: eighties

WordReference Random House Learner's Dictionary of American English © 2026

eight•y /ˈeɪti/   n. [countable] , pl. eight•ies. 

1. a number, ten times eight.
2. a symbol for this number, as 80 or LXXX.
3. eighties, [plural] the numbers from 80 through 89, as in referring to the years of a lifetime or of a century or to degrees of temperature: [one's + ~]
   He's in his eighties (= He is between 80 and 89 years of age).
   [the + ~]
   The temperature is in the eighties.

eight•i•eth, adj. 

WordReference Random House Unabridged Dictionary of American English © 2026

eight•y  (ā′tē), n., pl. eight•ies, adj. 
n. 

1. a cardinal number, ten times eight.
2. a symbol for this number, as 80 or LXXX.
3. a set of this many persons or things.
4. eighties, the numbers, years, degrees, or the like, from 80 through 89, as in referring to numbered streets, indicating the years of a lifetime or of a century, or degrees of temperature.

adj. 

5. amounting to 80 in number.

• Middle English eighteti, Old English eahtatig. See eight, -ty¹ bef. 850

Collins Concise English Dictionary © HarperCollins Publishers::

eighty / ˈeɪtɪ/ noun ( -ies)

1. the cardinal number that is the product of ten and eight
   See also number1
2. a numeral, 80, LXXX, etc, representing this number
3. (plural) the numbers 80–89, esp a person's age or the year of a particular century
4. the amount or quantity that is eight times as big as ten
5. something represented by, representing, or consisting of 80 units

determiner

1. amounting to eighty: eighty pages of nonsense
2. (as pronoun): eighty are expected

Etymology: Old English eahtatig; related to Old Frisian achtig, Old High German ahtozug