fifty

UK: /ˈfɪfti/ US: /ˈfɪfti/ ,(fif′tē)

Inflections of 'fifty' (n): npl: fifties

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

fif•ty /ˈfɪfti/   n. [countable] , pl. -ties, adj. 

1. a cardinal number, ten times five.
2. a symbol for this number, as 50 or L.
3. fifties, the numbers from 50 through 59, as in referring to the years of a lifetime or of a century or to degrees of temperature:
   The temperature is in the fifties.
4. Informal Terms a fifty-dollar bill.

adj. [before a noun]

5. amounting to 50 in number.

fif•ti•eth, adj., n. [countable]

WordReference Random House Unabridged Dictionary of American English © 2026

fif•ty  (fif′tē), n., pl. -ties, adj. 
n. 

1. a cardinal number, ten times five.
2. a symbol for this number, as 50 or L.
3. a set of this many persons or things.
4. fifties, the numbers, years, degrees, or the like, from 50 through 59, as in referring to numbered streets, indicating the years of a lifetime or of a century, or degrees of temperature:
   She lives in the East Fifties. He's in his late fifties. It's going to be in the fifties again today.
5. Informal Terms a fifty-dollar bill:
   He had a fifty and two tens in his wallet.

adj. 

6. amounting to 50 in number.

• bef. 900; Middle English; Old English fīftig. See five, -ty¹

Collins Concise English Dictionary © HarperCollins Publishers::

fifty / ˈfɪftɪ/ noun ( -ties)

1. the cardinal number that is the product of ten and five
2. a numeral, 50, L, etc, representing this number
3. something represented by, representing, or consisting of 50 units

determiner

1. amounting to fifty: fifty people
2. (as pronoun): fifty should be sufficient

Etymology: Old English fīftig