thirty

noun thir·ty \ ˈthər-tē \

Definition of thirty

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

play \-tē-əth\ adjective or noun

thirty

adjective

thirty

pronoun, plural in construction

thirtyish

play \-ish\ adjective

Examples of thirty in a Sentence

  1. The temperature outside is in the high thirties.

  2. He is in his thirties.

Recent Examples of thirty from the Web

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.

Origin and Etymology of 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

Other Number-Related Terms


THIRTY Defined for English Language Learners

thirty

noun

Definition of thirty for English Language Learners

  • : the number 30

  • thirties : the numbers ranging from 30 to 39

  • : a set of years ending in digits ranging from 30 to 39


THIRTY Defined for Kids

1

thirty

adjective thir·ty \ ˈthər-tē \

Definition of thirty for Students

: being three times ten

2

thirty

noun

Definition of thirty for Students

: three times ten : 30


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