thir·​ty | \ ˈthər-tē How to pronounce thirty (audio) \
plural thirties

Definition of thirty

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 30wrote thirty on the last page of the story
4 : the second point scored by a side in a game of tennis

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Other Words from thirty

thirtieth \ ˈthər-​tē-​əth How to pronounce thirtieth (audio) \ adjective or noun
thirty adjective
thirty pronoun, plural in construction
thirtyish \ ˈthər-​tē-​ish How to pronounce thirtyish (audio) \ 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 Portland, who wore sleek frameless glasses, a black puffy vest, and a bright pink cashmere scarf, had enlisted in her twenties, and gone to nearby Grinnell College in her thirties, receiving a B.A. in European history. Rob Fischer, The New Yorker, "Elizabeth Warren’s Final Pitch in Iowa," 28 Jan. 2020 She is played as a child by Ryan Kiera Armstrong, as a young teenager by Lulu Wilson, in her twenties and thirties by Alicia Vikander and from her forties to the present by Julianne Moore. David Rooney, The Hollywood Reporter, "'The Glorias': Film Review | Sundance 2020," 27 Jan. 2020 His memoir, starting with life here in the thirties and forties, is the main course of Reflections and it is presented with side dishes of state and local history, travelogues, biographies, philosophy and fishing lore., "Community News For The Windsor Edition," 31 Oct. 2019 The majority of the crowd was in its twenties and thirties. Chris Payne, Billboard, "Riot Fest Founder Mike Petryshyn Reveals the Legendary Band Reunions He's Still Trying For: Q&A," 24 Sep. 2019 The Ukrainian television series Servant of the People, which aired from 2015 until this year, is the story of Vasyl Holoborodko, a dedicated history teacher in his late thirties who lives with his parents. Sophie Pinkham, The New York Review of Books, "Ukraine’s New Leading Man," 17 June 2019 By that time, Norgay was in his late thirties and had gained a reputation as one of the best indigenous Himalayan guides. Freddie Wilkinson, National Geographic, "He’s the last surviving member of the first expedition to summit Everest," 17 June 2019 It was also announced that the show's creator, Terri Minsky, would be returning, and that the series would follow Lizzie, now in her thirties and living in New York. Amy Mackelden, Harper's BAZAAR, "The Lizzie McGuire Reboot Is Officially Happening. Here's Everything You Need to Know.," 10 Nov. 2019 The mahout was in his thirties and his whole family had worked with elephants. National Geographic, "Episode 3: The Hidden Cost of the Perfect Selfie," 29 Oct. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'thirty.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of thirty

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

History and Etymology for thirty

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

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Time Traveler for thirty

Time Traveler

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

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Statistics for thirty

Last Updated

14 Feb 2020

Cite this Entry

“Thirty.” Dictionary, Merriam-Webster, Accessed 26 Feb. 2020.

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More Definitions for thirty


How to pronounce thirty (audio)

English Language Learners Definition of thirty

: the number 30
: the numbers ranging from 30 to 39
: a set of years ending in digits ranging from 30 to 39


thir·​ty | \ ˈthər-tē How to pronounce thirty (audio) \

Kids Definition of thirty

 (Entry 1 of 2)

: being three times ten



Kids Definition of thirty (Entry 2 of 2)

: three times ten : 30

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More from Merriam-Webster on thirty

Rhyming Dictionary: Words that rhyme with thirty

Spanish Central: Translation of thirty

Nglish: Translation of thirty for Spanish Speakers

Britannica English: Translation of thirty for Arabic Speakers

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