Eldest vs. Oldest: What’s the Difference?

When it comes to the comparative and superlative forms of “advanced age,” English grammar gives us a strange choice. It’s correct to say “elder brother.” Then again, you could also say “older brother.” Both words mean (almost) the same thing, and they can be used in the same context. So, why do we have two different words that sound so similar?

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Both eld- and old- forms come from the same root word, eald. The Online Etymology Dictionary confirms, the Anglian ald and the West Saxon/Kentish eald originated with the Proto-Germanic althaz, which means “grown up, adult.” Althaz derived from Proto-Indo-European. The common ancestor of all Indo-European languages, Proto-Indo-European used the root al-, meaning “to grow, nourish.” From this common origin, the word eald/ald developed, and it dates back to the writing of Beowulf (possibly 700-750 AD). 

The blog Grammarphobia describes how the word evolved: The superlative adjective ‘eldest’ was first recorded around 897 in King Alfred’s Pastoral Care.” Of course, the spelling of Old English words varied considerably from one record to the next. The spelling used in Pastoral Care (ieldesta) did not look anything like the modern spelling of “eldest”. Over the years, English writers recorded eald/ald and its comparative and superlative forms with a wide variety of spellings: ieldran, yldra, ealdor, ylde, etc. 

In addition to the use of ald/eald as an adjective and a noun, the verb ælden /elden, meaning “to grow old,” gained traction in the Middle Ages. Eventually, this verb fell into disuse. 

Ultimately, you would expect the popularization of the printing press to eliminate variant spellings. For many words, the 15th-16th century proved a time of consolidation. Historians sometimes credit the publisher William Caxton with standardizing English spelling in the 15th century; however, in truth, a new standard emerged gradually from the growth of the publishing industry as a whole. By the 16th century, the Online Etymology Dictionary explains that “eldest” had been superseded by “oldest” in most contexts. 

Whereas other words saw their variant spellings disappear over time, the word “eldest” managed to stick around. The question is, why?

The Difference Between Eldest and Oldest

In most contexts, “oldest” and “older” have replaced “eldest” and “elder.” 

Here are a few examples:

  • He is getting older > He is getting elder
  • Becky is older than Tom > Becky is elder than Tom
  • He is getting older > He is getting elder
  • That house is the oldest on the block > That house is the eldest on the block
  • She is the oldest student in the world > She is the eldest student in the world 

The modern use of “elder” and “eldest” has a very narrow scope. We only use eld- forms in cases that benefit from more specificity. 

First of all, the eld- forms only apply to people. You wouldn’t mention the “eldest apple” in the bunch, but the “eldest daughter” makes sense. Secondly, we use “elder” and “eldest” as limiting adjectives. Dictionary.com defines a limiting adjective as, “One of a small group of adjectives that modify the nouns to which they are applied by restricting rather than describing or qualifying.” Indeed, describing a person as the “eldest brother” only makes sense in relationship to a set of younger brothers. The adjective “eldest” restricts the noun “brother,” as if to say, “This brother (not that brother).” 

For that reason, you would describe someone as the “oldest person in the country” rather than the “eldest person in the country.” It’s only appropriate to use “eldest” when you want to point to one person within a limited set of other people. For example, you might say, “She is the eldest of the ten citizens who voted.” 

“The eldest” and “the elder” can also be used as nouns when the comparison to another person or set of people is clear. The phrase “she is the eldest” only works when the reader or listener understands to whom (family members, other students, fellow passengers) she is being compared. We use “elder” as the limiting adjective in a set of two and “eldest” as the limiting adjective for a set of three or more. 

Here’s another difference. “Older” and “old” can be used as adverbs. For example, you can mention an “older toothless woman” or an “old black sweater.” “Elder” cannot be used in this manner. 

In almost all cases, “oldest” can be used instead of “eldest.” “Eldest” simply adds specificity. For example, identifying someone as an “older” brother may lead to confusion. Is he the absolute oldest child, the eldest brother, or relationally older than another sibling? When you identify someone as the elder son, they are understood to be the oldest of a set of two sons.  


Merriam-Webster defines “oldest” as the superlative form of “old”. As a noun, “old” meansone of a specified age” or “old or earlier time.” There are a number of definitions for the adjective form of the word. Some of them include, “dating from the remote past,” “of longstanding,” “distinguished from an object of the same kind by being of an earlier date,” “of, relating to, or originating in a past,” “advanced in years,” and “showing the characteristics of age.”

In contrast, the word “eldest” only has one definition: “of the greatest age or seniority.” 


According to Thesaurus.com, synonyms for oldest include:

  • earliest
  • first
  • original
  • primeval

Thesaurus.com lists the following as primary synonyms for eldest:

  • aged
  • ancient
  • decrepit
  • elderly
  • gray
  • mature
  • tired
  • venerable

Other Words and Phrases

An elder statesman is a senior and respected member of an organization. More specifically, Merriam-Wester gives the alternate definition: “A retired statesman who unofficially advises current leaders.” This is an idiomatic expression, since he phrase “elder statesman” does not exclusively refer to either a political figure or the older of a set of two.

The phrase “elders and betters” is a common way to refer to people who are older and more important than another person.  

“The oldest trick in the book” is another idiom. Cambridge Dictionary defines it as, “A way of tricking someone that is still effective although it has been used a lot before.”


  1. https://www.etymonline.com/search?q=eldest
  2. https://www.etymonline.com/word/old?ref=etymonline_crossreference
  3. https://www.merriam-webster.com/dictionary/oldest
  4. https://www.merriam-webster.com/dictionary/eldest
  5. https://www.merriam-webster.com/words-at-play/difference-between-elder-eldest-and-older-oldest
  6. https://dictionary.cambridge.org/us/grammar/british-grammar/elder-eldest-or-older-oldest
  7. https://www.grammarphobia.com/blog/2017/02/elder-older.html
  8. https://www.britannica.com/topic/Beowulf
  9. https://dictionary.cambridge.org/us/dictionary/english/oldest-trick-in-the-book