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 30 wrote 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

Roger Federer, Rafael Nadal and Novak Djokovic, all comfortably into their thirties, remain the foremost players on the men’s tennis tour., "Roger Federer, Rafael Nadal still dominate, evidence this isn’t tennis’ greatest era: 2019 Wimbledon," 8 July 2019 Painted when the artist was in his thirties, the monumental works prefaced Tiepolo’s later Grand Mannerist creations in such far-flung locales as Bavaria and Spain. Meilan Solly, Smithsonian, "The Frick Revives 18th-Century Frescoes Destroyed During World War II," 3 July 2019 Frannie is in her thirties, broke and disheartened by her lack of progress on all fronts. Renee Valois, Twin Cities, "Park Square’s ‘Jefferson Township Sparkling Junior Talent Pageant’ is over-the-top absurd — and hilarious," 29 June 2019 There’s a difference between seeing that as a child and not seeing it until your thirties. Megan Angelo, Glamour, "Booksmart Is the First Truly Evolved High School Movie," 24 May 2019 In the first, Conversations with Friends, Frances and Bobbi, two best friends in their early twenties who used to date and occasionally sleep together, fall for Nick and Melissa, a couple in their thirties. Madeleine Schwartz, The New York Review of Books, "How Should a Millennial Be?," 18 Apr. 2019 The men who led each side—Yakubu Gowon on the federal side and Chukwuemeka Ojukwu of Biafra—were in their mid-thirties. Emmanuel Iduma, The New York Review of Books, "‘Gone Like a Meteor’: Epitaph for the Lost Youth of the Biafran War," 30 May 2019 During the war, Auto Union built tank engines designed by Wilhelm Maybach, Gottlieb Daimler's original business partner who competed against Horch with his own extravagant cars during the twenties and thirties. Clifford Atiyeh, Car and Driver, "The Audi A8 May Go Electric and Ultra-Luxurious with a New High-End Model," 25 May 2019 The man, who is in his thirties, immediately reported the incident to his superior. Noemie Bisserbe And Francis X. Rocca, WSJ, "Vatican Envoy to France Is Investigated for Sexual Assault Allegation," 15 Feb. 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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Statistics for thirty

Last Updated

18 Jul 2019

Look-up Popularity

Time Traveler for thirty

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

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More Definitions for thirty



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

Comments on thirty

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characterized by aphorism

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