Dictionary.com
Thesaurus.com

eightieth

American  
[ey-tee-ith] / ˈeɪ ti ɪθ /

adjective

  1. next after the seventy-ninth; being the ordinal number for 80.

  2. being one of 80 equal parts.


noun

  1. an eightieth part, especially of one (1/80).

  2. the eightieth member of a series.

eightieth British  
/ ˈeɪtɪɪθ /

adjective

  1. (usually prenominal)

    1. being the ordinal number of eighty in numbering or counting order, position, time, etc: often written 80th

    2. ( as noun )

      the eightieth in succession

"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

noun

    1. one of 80 approximately equal parts of something

    2. ( as modifier )

      an eightieth part

  1. the fraction equal to one divided by 80 ( 1/ 80 )

"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

Etymology

Origin of eightieth

1350–1400; Middle English eightetithe, Old English ( hund ) eahtatigotha eightieth. See eighty, -th 2

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

At the time, scientists thought that something as small as viroids, which are one eightieth the size of many viruses, were too minuscule to cause an infection.

From New York Times • May 8, 2023

The Golden Globes, which is now in its eightieth year, honours work in both film and television.

From BBC • Jan. 11, 2023

“Most actors,” he writes, “are wise enough to know that you’re often second, third or even eightieth choice for the role.”

From Washington Post • Nov. 7, 2022

Entering his eightieth decade he hasn’t lost his taste for that whiff of adventure, either in his walking or his writing.

From The Guardian • Apr. 14, 2019

On his one hundred and eightieth day at the dump, salvation arrived for Edward in a most unusual form.

From "The Miraculous Journey of Edward Tulane" by Kate DiCamillo