eightieth

eightieth — ordinal number

IPA/ˈeɪtiəθ/
KK[ˈetiɪθ]IPA/ˈeɪtiəθ/

1. the word for the number 80th in a sequence — meaning that there are seventy-nine

1.ordinal numberA2
Definition

the word for the number 80th in a sequence — meaning that there are seventy-nine items or people before it and any number may follow after it.

Example

The Watanabe family celebrated their grandfather's eightieth birthday with a big party.

ordinal before noun: eightieth birthday

Takeshi finished in eightieth place out of over two hundred runners in the marathon.

ordinal before noun: eightieth place

Common collocations
  • eightieth birthday
  • eightieth place
  • eightieth anniversary
  • eightieth chapter
  • eightieth year

Grammar Patterns

the eightieth + noun

eightieth + noun (when a person's name follows)

Usage Note

Usually used with the definite article 'the', as in 'the eightieth item on the list'. When the ordinal comes before a person's name (e.g. 'eightieth Pope'), 'the' is omitted.

Common Mistakes

This is my eighty birthday.
This is my eightieth birthday.
Ordinal numbers (eightieth) show position; cardinal numbers (eighty) show quantity.

eightieth — noun

IPA/ˈeɪ.ti.əθ/
KK[ˈetiɪθ]IPA/ˈeɪ.t̬i.əθ/

eightieth — adjective

Word family

Synonym discussion

Sense: adjective/1

'Eightieth' is the only standard English word for the ordinal position 80. Unlike lower ordinals such as 'first', 'second', or 'third', which have unrelated forms, 'eightieth' is regularly formed by adding '-ieth' to 'eighty'. No synonyms exist for this specific number — '80th' is simply the numeral version used in informal writing, dates, and lists. In contexts such as 'the eightieth anniversary' or 'the eightieth chapter', the numeral form '80th' is more common in headlines and tables, while the word form appears in formal prose and speech. For example: 'Her eightieth birthday' (more natural in speech) vs. 'Her 80th birthday' (common in written invitations). The two forms are interchangeable in meaning but differ in register.

eightieth ↗eightieth in ordereightieth position

Common collocations

Nouns

Phrases

  • the eightieth of
  • an eightieth of
  • in eightieth place

Prepositions

Etymology

Old EnglishMiddle EnglishEnglish

The word 'eightieth' comes from Old English 'eahtatigða', formed from 'eahtatig' (eighty) plus the ordinal suffix '-ða' (which later became '-th'). It is related to Old High German 'ahtozugōsto' and follows the same pattern as other '-ieth' ordinals such as 'sixtieth' and 'seventieth'. The modern spelling settled in Middle English as 'eightithe', later adjusting to 'eightieth' as pronunciation shifted.