eldest

American  

[el-dist] / ˈɛl dɪst /

adjective

1. oldest; firstborn; of greatest age: eldest sister;

   eldest brother;

   eldest sister;

   eldest born.

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eldest British  

/ ˈɛldɪst /

adjective

1. being the oldest, esp the oldest surviving child of the same parents

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Etymology

Origin of eldest

First recorded before 900; Middle English; Old English eldesta, superlative of eald, ald; see old

Explanation

Someone who's described as eldest in their family was born first. Your eldest sister is the oldest one. Use the adjective eldest when you're describing people in terms of birth order: the oldest is the eldest. Your eldest friend is older than your other friends. You can also use the word as a noun, meaning "firstborn." Your mom might introduce you by saying, "This is my eldest." It's a somewhat formal, old fashioned word, much less popular today than "oldest."

Example Sentences

Related: My former mother-in-law took out a life-insurance policy on my eldest child.

From MarketWatch • Apr. 14, 2026

The eldest, Walter, was a Caracas judge, having followed his mother into law.

From The Wall Street Journal • Mar. 29, 2026

Reza Pahlavi, the eldest son of the last shah of Iran and pretender to the throne, was a scheduled speaker, and the event was packed with Iranian monarchists.

From Slate • Mar. 27, 2026

Much of Keough’s story in that first episode was focused on her eldest son, Shane.

From Los Angeles Times • Mar. 24, 2026

They were now the property of the eldest son by Leon’s second marriage and installed in a castle somewhere in the Scottish Highlands.

From "Atonement" by Ian McEwan

Related Words

• earlier