orthonormal

adj

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

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

The verdict

“orthonormal” is uncommon English (frequency #94,080 among 15,494 “O” headwords), classed as an adjective. The kind of spelling people second-guess.

#94,080
frequency rank, English
15,494
“O” headwords

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - Of a set of vectors, both orthogonal and normalized.

Key facts for orthonormal
PropertyValue
Headwordorthonormal
LanguageEnglish
Part of speechAdjective
Letters11
Frequency rank#94,080
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Where “orthonormal” 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). orthonormal 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

orthonormal is uncommon English at frequency #94,080 among 15,494 “O” headwords, classed as anadjective. Rarity is why readers land here mid-draft. 2 senses are on record.

Zero misspellings are on record for orthonormal in our index, a sign its spelling follows regular English conventions. This headword has no recorded confusable partner, which tends to mean the word is visually distinctive enough to stand on its own.

Etymologically, the entry records: Blend of orthogonal + normal, equivalent to ortho- + normal. The correct English form is orthonormal, spelled O-R-T-H-O-N-O-R-M-A-L.

Definition

  1. 1
    Of a set of vectors, both orthogonal and normalized.
  2. 2
    Of a linear transformation: that preserves both angles and lengths.

Etymology

Blend of orthogonal + normal, equivalent to ortho- + normal.

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 "orthonormal"?
"orthonormal" is spelled O-R-T-H-O-N-O-R-M-A-L.
What does "orthonormal" mean?
As an adjective, "orthonormal" means: Of a set of vectors, both orthogonal and normalized.
What is the origin of the word "orthonormal"?
Blend of orthogonal + normal, equivalent to ortho- + normal. 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 “orthonormal”

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

  • The one correct English spelling is O-R-T-H-O-N-O-R-M-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