thirty

noun

thir·​ty ˈthər-tē How to pronounce thirty (audio)
plural thirties
1
: a number equal to three times 10 see Table of Numbers
2
thirties plural : the numbers 30 to 39
specifically : the years 30 to 39 in a lifetime or century
3
: a sign of completion : end
usually written 30
wrote thirty on the last page of the story
4
: 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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Back in the thirties, people thought nuclear power was going to revolutionize the world in a good way. Mike Fleming Jr, Deadline, 27 June 2025 But, that doesn’t mean that throughout his teens, twenties and thirties he wouldn’t be subjected to the scrutiny Muslim men have received in New York over the last quarter century. Steven W. Thrasher june 26, Literary Hub, 26 June 2025 The rest of Shahn’s résumé from the thirties reads like that of a lefty artist plucked from central casting. Zachary Fine, New Yorker, 24 June 2025 In an effort to overcome grief and find herself again, Hollis gets the idea to host a weekend away at her house on Nantucket with three friends from different stages in her life: her childhood, her twenties, thirties, and one surprise fifth star. Joe Otterson, Variety, 24 June 2025 See All Example Sentences for thirty

Word History

Etymology

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

Browse Nearby Words

Cite this Entry

“Thirty.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/thirty. Accessed 3 Jul. 2025.

Kids Definition

thirty

noun
thir·​ty ˈthərt-ē How to pronounce thirty (audio)
plural thirties
1
: a number equal to three times 10 see number
2
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

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