thir·​ty ˈthər-tē How to pronounce thirty (audio)
plural thirties
: a number equal to three times 10 see Table of Numbers
thirties plural : the numbers 30 to 39
specifically : the years 30 to 39 in a lifetime or century
: a sign of completion : end
usually written 30
wrote thirty on the last page of the story
: the second point scored by a side in a game of tennis
thirtieth adjective or noun
thirty adjective
thirty pronoun, plural in construction
thirtyish adjective

Examples of thirty in a Sentence

The temperature outside is in the high thirties. He is in his thirties.
Recent Examples on the Web The second-most expensive Magnificent Seven stock is Nvidia Corp. at around 36 times forward earnings, while the rest trade between the low twenties and low thirties. Esha Day, Fortune, 11 Feb. 2024 Production of the collagen that keeps the skin plump and firm begins to dwindle in our late twenties and early thirties, but a thoughtful daily routine can help with retaining and boosting it—without resorting to the needle. Ana Morales, Vogue, 10 Feb. 2024 Among the loudest evangelists was a naturopath named Paul C. Bragg, who, in the nineteen-twenties and thirties in Los Angeles, became a wellness adviser to the stars and then to the broader public. Hannah Goldfield, The New Yorker, 5 Feb. 2024 And that’s going to appeal to somebody in their twenties, thirties, or forties. Dylan Sloan, Fortune, 29 Jan. 2024 In the nineteen-twenties and thirties, W.O. Kermack and A.G. McKendrick, colleagues at the Royal College of Physicians, in Edinburgh, took the work a step further. Dan Rockmore, The New Yorker, 15 Jan. 2024 The 'Law & Order: SVU' star writes a first-person essay about her experience as part of this week's PEOPLE cover story A man raped me in my thirties. Mariska Hargitay, Peoplemag, 10 Jan. 2024 The women generally fell into two categories: early thirties or younger and childless, like me, or former teen moms entering a new phase of their lives. Emily Gogolak, Harper's Magazine, 9 Jan. 2024 Both are in their early thirties, with a wardrobe that suggests Margaret Thatcher is still Prime Minister. David Fear, Rolling Stone, 22 Dec. 2023 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'thirty.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


Middle English thritty, from thritty, adjective, from Old English thrītig, from thrītig group of 30, from thrīe three + -tig group of ten; akin to Old English tīen ten

First Known Use

before the 12th century, in the meaning defined at sense 1

Time Traveler
The first known use of thirty was before the 12th century

Dictionary Entries Near thirty

Cite this Entry

“Thirty.” Dictionary, Merriam-Webster, Accessed 27 Feb. 2024.

Kids Definition


thir·​ty ˈthərt-ē How to pronounce thirty (audio)
plural thirties
: a number equal to three times 10 see number
plural : the numbers 30 to 39
especially : the years 30 to 39 in a lifetime or century
thirtieth noun or adjective
thirty adjective or pronoun

More from Merriam-Webster on thirty

Last Updated: - Updated example sentences
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