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

Keep scrolling for more

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 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 By the 2000s, over half of the black men in Milwaukee County in their thirties had state prison records. Caleb Gayle, The New Republic, "Inside the “Most Incarcerated” Zip Code in the Country," 15 Oct. 2019 Naomi Patel was our age—late-ish thirties—and had a very reassuring and competent manner. Joseph O’neill, The New Yorker, "The Flier," 4 Nov. 2019 Now in North Korea, Kim Jong Un is the only one in his thirties in the North Korean leadership. Laignee Barron / Taipei, Time, "'Materialism Will One Day Bring Change.' Why a Senior Defector Believes North Korea's Days Are Numbered," 19 Sep. 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.

See More

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

Keep scrolling for more

Learn More about thirty

Time Traveler for thirty

Time Traveler

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

See more words from the same century

Statistics for thirty

Last Updated

3 Jan 2020

Cite this Entry

“Thirty.” The Dictionary, Merriam-Webster Inc., Accessed 19 January 2020.

Keep scrolling for more

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

Keep scrolling for more

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

What made you want to look up thirty? Please tell us where you read or heard it (including the quote, if possible).


to insert between existing elements

Get Word of the Day daily email!

Test Your Vocabulary

The Eponym Quiz

  • rubens painting
  • Which is the best synonym of bowdlerize?
Spell It

Can you spell these 10 commonly misspelled words?

Syn City

Test Your Knowledge - and learn some interesting things along the way.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!