eldest

eldest — adjective

1. being the person with the greatest age among three or more siblings or family me

1.adjectiveB1
Definition

being the person with the greatest age among three or more siblings or family members — for example, the child who was born first in a family with three children.

Example

Andrei is the eldest of three brothers in his family.

As the eldest sibling, Zuri often helps her younger sisters with homework.

eldest + noun phrase describing family role

Common collocations
  • eldest son
  • eldest daughter
  • eldest child
  • eldest sibling
  • eldest brother
  • eldest sister
  • the eldest of
Synonyms
  • oldest

    broader term that works for people and things; 'oldest' is neutral while 'eldest' is specifically for family

  • first-born

    emphasises order of birth rather than age; slightly more formal or literary

  • most senior

    used for rank or position rather than family; often in professional contexts

Antonyms
  • youngest

    the direct opposite in birth order

Grammar Patterns

the + eldest + noun

possessive + eldest + noun

eldest + of + plural noun

Usage Note

Use 'eldest' only for family members (siblings, children). For non-family contexts — buildings, objects, or general groups of people — use 'oldest' instead. Also requires at least three people; for a family with only two children, use 'older' or 'elder'.

Common Mistakes

She is my eldest sister' (when you have only one sister).
She is my older sister.
'eldest' implies at least three siblings; for two siblings, use 'older' or 'elder'.
That is the eldest building in the city.
That is the oldest building in the city.
'eldest' is only used for family members, not objects or buildings.

eldest — noun

Word family

Synonym discussion

Sense: adjective/1

'Eldest' and 'oldest' are both superlative forms meaning 'most advanced in age', but their usage differs sharply. 'Eldest' is almost always restricted to family relationships and requires at least three people. 'Oldest' is far more versatile — it can describe people, objects, buildings, or abstract concepts ('the oldest tree in the park'). 'Elder' (as an adjective, not the noun) compares two people within a family ('my elder brother'), while 'eldest' needs three or more. 'First-born' specifically highlights the order of birth rather than age itself and tends to sound more formal or literary. For example: 'Ramón's eldest brother drives a bus' (three or more brothers), but 'Ramón's elder brother is a teacher' (exactly two brothers); and 'the oldest building in town' not 'the eldest building'.

eldest ↗oldestelder ↗first-born

Common collocations

Nouns

Phrases

  • the eldest of
  • the eldest among
  • the eldest in

Prepositions

Etymology

Old EnglishMiddle EnglishEnglish

Comes from Old English 'ieldest', the superlative form of 'eald' (meaning old). The word has been used to describe family birth order since the early medieval period, and its form evolved through Middle English 'eldeste' into the modern 'eldest'. The 'eald' root also gives us 'elder', 'old', and 'elderly'.