[ thur-tee ]
/ ˈθɜr ti /
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noun, plural thir·ties.
a cardinal number, 10 times 3.
a symbol for this number, as 30 or XXX.
a set of this many persons or things.
Printing, Journalism. 30-dash.
thirties, the numbers, years, degrees, or the like, from 30 through 39, as in referring to numbered streets, indicating the years of a lifetime or of a century, or referring to degrees of temperature: He works in the East Thirties. She must be in her thirties. The temperature was in the thirties yesterday.
amounting to 30 in number.
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Origin of thirty

before 900; Middle English thritty,Old English thrītig, equivalent to thrīthree + -tig-ty1; cognate with Dutch dertig,German dreissig,Old Norse thrjātīu
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022

How to use thirty in a sentence

British Dictionary definitions for thirty

/ (ˈθɜːtɪ) /

noun plural -ties
the cardinal number that is the product of ten and threeSee also number (def. 1)
a numeral, 30, XXX, etc, representing this number
(plural) the numbers 30–39, esp the 30th to the 39th year of a person's life or of a century
the amount or quantity that is three times as big as ten
something representing, represented by, or consisting of 30 units
  1. amounting to thirtythirty trees
  2. (as pronoun)thirty are broken

Word Origin for thirty

Old English thrītig; see three, -ty 1
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