thirtieth

American  

[thur-tee-ith] / ˈθɜr ti ɪθ /

adjective

1. next after the twenty-ninth; being the ordinal number for 30.

2. being one of 30 equal parts.

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noun

thirtieths plural

1. a thirtieth part, especially of one (1/30).

2. the thirtieth member of a series.

thirtieth British  

/ ˈθɜːtɪɪθ /

adjective

1. (usually prenominal)

   1. being the ordinal number of thirty in counting order, position, time, etc: often written 30th

   2. ( as noun )

      the thirtieth of the month

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noun

1. 1. one of 30 approximately equal parts of something

   2. ( as modifier )

      a thirtieth part

2. the fraction equal to one divided by 30 ( 1/ 30 )

Other Word Forms

Noun Inflected Forms

• thirtieths
  plural

Etymology

Origin of thirtieth

before 900; thirty + -eth ²; replacing Middle English thrittythe, Old English thrītegtha

Example Sentences

See Examples For:

thirtieth thirtieths

The difference: Your guests won’t have to feign enthusiasm after the thirtieth photo of you “holding up” the Leaning Tower of Pisa.

From The Wall Street Journal ● Dec. 4, 2025

After the thirtieth consecutive month without rain, the townsfolk of San Francisco de Conchos in the northern Mexican state of Chihuahua gather to plead for divine intervention.

From BBC ● Jul. 13, 2025

Find the thirtieth term of a sequence where the first term is 16 and the common difference is −5.

From Textbooks ● May 6, 2020

It was the two hundred and thirtieth time he has played golf—usually at one of his seventeen clubs—out of his nine hundred and sixty-one days in the Presidency.

From The New Yorker ● Sep. 10, 2019

“Principal Rivera handpicked the kids that fit her picture of what this thirtieth anniversary celebration should look like. Us? Our loud punk band? Not part of that picture.”

From "The First Rule of Punk" by Celia C. Pérez

Above twenty-nine thirtieths of the profession submitted to the law.

From The History of England, from the Accession of James II — Volume 3 by Macaulay, Thomas Babington Macaulay, Baron