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.

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noun

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

2. the eightieth member of a series.

ˈeightieth 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

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noun

1. 1. one of 80 approximately equal parts of something

   2. ( as modifier )

      an eightieth part

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

Etymology

Origin of eightieth

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

Example Sentences

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

“In a hotel mirror, I have seen with surprise an old man in his eightieth year, then forgotten him,” Thubron wrote.

From Washington Post • Sep. 29, 2021

My eightieth birthday had gone on for a year.

From The New Yorker • Oct. 19, 2015

Just before her eightieth birthday, a reporter from the Houston Chronicle visited.

From "The Woman All Spies Fear" by Amy Butler Greenfield