[ fawr-tee ]
See synonyms for forty on
noun,plural for·ties.
  1. a cardinal number, ten times four.

  2. a symbol for this number, as 40 or XL or XXXX.

  1. a set of this many persons or things.

  2. forties, the numbers, years, degrees, or the like, from 40 through 49, as in referring to numbered streets, indicating the years of a lifetime or of a century, or degrees of temperature: His office is in the West Forties. Her parents are in their forties. The temperature will be in the forties.

  1. amounting to 40 in number.

Origin of forty

before 950; Middle English fourti,Old English fēowertig (cognate with Old Frisian fiuwertich,Old High German fiorzug,German vierzig). See four, -ty1

Words Nearby forty Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use forty in a sentence

British Dictionary definitions for forty


/ (ˈfɔːtɪ) /

nounplural -ties
  1. the cardinal number that is the product of ten and four: See also number (def. 1)

  2. a numeral, 40, XL, etc, representing this number

  1. something representing, represented by, or consisting of 40 units

    • amounting to forty: forty thieves

    • (as pronoun): there were forty in the herd

Origin of forty

Old English fēowertig

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012