eighty

eighty — noun

1. the number that comes after seventy-nine and is written as the digit 80.

1.nounA2
Definition

the number that comes after seventy-nine and is written as the digit 80.

Example

Layla wrote the number eighty on the board for her classmates to copy.

eighty as a noun referring to the number itself

Adisa's grandmother turned eighty last week and had a big party.

Common collocations
  • eighty years old
  • eighty people
  • page eighty
  • turn eighty
  • eighty percent
Synonyms
  • four score

    literary or historical use; made famous by Lincoln's Gettysburg Address, but not used in everyday speech

Grammar Patterns

eighty + plural noun

the number eighty

Usage Note

When used as a determiner, 'eighty' goes directly before a plural noun without 'of' — say 'eighty students', not 'eighty of students'. As a noun, it can be the subject or object of a sentence: 'Eighty is an even number.'

Common Mistakes

My grandmother is eighty years.
My grandmother is eighty years old.
In English, stating a person's age requires 'years old' or 'years of age' at the end.
There are eighty of students in the hall.
There are eighty students in the hall.
'eighty' as a determiner goes directly before the noun without 'of'.

2. the numbers from eighty to eighty-nine, used when stating a person's age range i

2.nounA2
Definition

the numbers from eighty to eighty-nine, used when stating a person's age range in years, the temperature in degrees, or a historical decade — for example, someone who is in their eighties is between 80 and 89 years old.

Example

Lakshmi's great-aunt is in her eighties but still runs a small shop.

in one's eighties — age range

The temperature climbed to the high eighties during the summer heatwave.

in the high eighties — temperature range

Common collocations
  • in one's eighties
  • in the eighties
  • in her early eighties
  • in his late eighties
  • the high eighties
  • the mid-eighties

Grammar Patterns

in one's eighties

in the eighties

in [her/his/their] early/mid/late eighties

Usage Note

This sense always uses the plural form 'eighties'. Never use the singular 'eighty' for this meaning. Common patterns: 'in one's eighties' (age), 'in the eighties' (temperature or decade), and 'early/mid/late eighties' for more precise ranges. The decade sense refers specifically to the 1980s.

Common Mistakes

My uncle is in his eighty.
My uncle is in his eighties.
The plural form 'eighties' is required when talking about an age range from 80 to 89.
The temperature is in the eighty.
The temperature is in the eighties.
Use the plural form for temperature ranges as well.

Word family

Synonym discussion

Sense: noun/1

Both 'eighty' and 'four score' mean the number 80, but they belong to very different registers. 'Eighty' is the standard word used in all everyday contexts — telling age ('eighty years old'), counting ('eighty people'), prices ('eighty dollars'), and measurements. 'Four score' is a literary or historical expression that comes from counting by twenties (a 'score' equals twenty). It is best known from Abraham Lincoln's Gettysburg Address ('Four score and seven years ago…') but sounds extremely old-fashioned in modern conversation. Use 'eighty' for any practical situation; reserve 'four score' only for historical quotations or deliberate poetic effect.

eighty ↗four score

Common collocations

Nouns

Phrases

  • eighty years old
  • in the eighties
  • in one's eighties
  • page eighty
  • turn eighty

Prepositions

Etymology

Old EnglishMiddle EnglishEnglish

The word 'eighty' comes from Old English 'eahtatig', which was formed by combining 'eahta' (eight) with '-tig' (a suffix meaning 'group of ten'). This structure — a number plus a ten-group ending — is shared with other English numbers like sixty, seventy, and ninety. In later Middle English the word changed to 'eighteti', and by the 1500s the modern spelling 'eighty' became standard. The same pattern appears in German 'achtzig' and Dutch 'tachtig', because all three languages come from the same Germanic root.