equilateral

adj

By · According to Wiktionary data (CC BY-SA) ·

"equilateral" is a 11-letter English headword indexed on PlainSpell.

The verdict

“equilateral” is uncommon English (frequency #62,874 among 18,836 “E” headwords), classed as an adjective. The kind of spelling people second-guess.

#62,874
frequency rank, English
18,836
“E” headwords

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - Having all the sides equal.

Key facts for equilateral
PropertyValue
Headwordequilateral
LanguageEnglish
Part of speechAdjective
Letters11
Frequency rank#62,874
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Where “equilateral” sits in English frequency

Every-word frequency runs from the handful of words we use constantly (left) to the long tail used once in a blue moon (right). equilateral lands here:

#1#100#1K#10K#100K
← used constantlyrarely used →

Scale is logarithmic (each tick is 10× rarer). Source: FrequencyWords open word-frequency list.

Rare enough to double-check

equilateral is uncommon English at frequency #62,874 among 18,836 “E” headwords, classed as anadjective. Rarity is why readers land here mid-draft. 4 senses are on record.

We couldn't generate a plausible misspelling set for equilateral, suggesting the orthography follows predictable English patterns. No close-neighbour confusable shows up for this headword in our dataset, suggesting its spelling stands apart enough that readers rarely confuse it with something else.

Etymologically, the entry records: From equi- + lateral. The correct English form is equilateral, spelled E-Q-U-I-L-A-T-E-R-A-L.

Definition

  1. 1
    Having all the sides equal.
  2. 2
    Having all the faces equal.
  3. 3
    Having the two sides equal, as a surface divisible by a longitudinal median line into two halves of the same form.
  4. 4
    Having all the convolutions of the shell in one plane, chiefly of foraminifers.

Etymology

From equi- + lateral.

This word in other languages

equilátero(Español)équilatéral(Français)gleichseitig(Deutsch)equilátero(Português)

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA); frequency ordering uses the FrequencyWords open word-frequency list (2018 English corpus, MIT). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "equilateral"?
"equilateral" is spelled E-Q-U-I-L-A-T-E-R-A-L.
What does "equilateral" mean?
As an adjective, "equilateral" means: Having all the sides equal.
What is the origin of the word "equilateral"?
From equi- + lateral. See the full etymology section above for more details.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Using “equilateral”

The practical upshot for anyone who landed here from a spell-check.

  • The one correct English spelling is E-Q-U-I-L-A-T-E-R-A-L - every other letter order is a misspelling in standard orthography.
  • Browse more English words and confusable pairs in the same reference. English words

Other uncommon English words near this rank

Data Source

Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list FrequencyWords open word-frequency list