Try Our Apps


Avoid these words. Seriously.


[thur-tee-ith] /ˈθɜr ti ɪθ/
next after the twenty-ninth; being the ordinal number for 30.
being one of 30 equal parts.
a thirtieth part, especially of one (1/30).
the thirtieth member of a series.
Origin of thirtieth
before 900; thirty + -eth2; replacing Middle English thrittythe, Old English thrītegtha Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
Cite This Source
Examples from the Web for thirtieth
Historical Examples
  • By the thirtieth time it has become a word like "snark" or "pobble."

    Alarms and Discursions G. K. Chesterton
  • She was one of those blondes who fade rapidly after their thirtieth year.

    Fruitfulness Emile Zola
  • And now if ye will do battle, come again on the thirtieth day from hence.

    Cyropaedia Xenophon
  • "In the thirtieth street station-house, sir," she briefly responded.

    The Masked Bridal Mrs. Georgie Sheldon
  • The Army of the Valley had its orders from Strasburg the night of the thirtieth.

    The Long Roll Mary Johnston
  • The delusion holding, he, at noon of the thirtieth, ordered a general advance.

    The Long Roll Mary Johnston
  • He had sons there himself, and a letter which he would read for the thirtieth time.

    The Long Roll Mary Johnston
  • She'll report for duty on the thirtieth, thank the powers which be.

    Peggy Stewart at School

    Gabrielle E. Jackson
  • At thirtieth Street he got off the car and walked west to Silver's place.

    From Place to Place

    Irvin S. Cobb
  • The paper-knife generally ceased to do duty before the thirtieth page.

    The Library Andrew Lang
British Dictionary definitions for thirtieth


(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
  1. one of 30 approximately equal parts of something
  2. (as modifier): a thirtieth part
the fraction equal to one divided by 30 (1/30)
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Cite This Source
Word Origin and History for thirtieth

Middle English threttyth, from Old English þritigoða; see thirty + -th (1). Respelled 16c. to conform to new spelling of thirty.

Online Etymology Dictionary, © 2010 Douglas Harper
Cite This Source

Word of the Day

Nearby words for thirtieth

Word Value for thirtieth

Scrabble Words With Friends