undulation

noun

"undulation" is a 10-letter English headword indexed on PlainSpell.

The verdict

“undulation” is uncommon English (outside the top frequency list), classed as a noun. The kind of spelling people second-guess.

Unranked
below top-frequency English
10
letters

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - An instance or act of undulating.

Key facts for undulation
PropertyValue
Headwordundulation
LanguageEnglish
Part of speechNoun
Letters10
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Where “undulation” sits in English frequency

undulation falls outside the top-100,000 ranked English words, the long-tail zone of technical, archaic, or low-frequency vocabulary, exactly where readers second-guess spellings most.

Beyond rank #100,000. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

undulation is uncommon English outside the top frequency list, classed as anoun. Rarity is why readers land here mid-draft. 7 senses are on record.

Our edit-distance generator produced no likely misspellings for undulation, and the word's spelling is regular enough that our generator found nothing worth flagging. 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 undulate + -ion, or borrowed from Medieval Latin undulātiō; compare French ondulation. The correct English form is undulation, spelled U-N-D-U-L-A-T-I-O-N.

Definition

  1. 1
    An instance or act of undulating.
  2. 2
    A wavy appearance or outline; waviness.
  3. 3
    A tremulous tone produced by a peculiar pressure of the finger on a string.
  4. 4
    A wavelike curve; a smooth and regular rise and fall.
  5. 5
    A wavelike motion of the air; electromagnetic radiation.
  6. 6
    A feeling as if of an undulatory motion about the heart.
  7. 7
    The distinctive motion of the matter within an abscess on being pressed when it is ripe for opening.

Etymology

From undulate + -ion, or borrowed from Medieval Latin undulātiō; compare French ondulation.

This word in other languages

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "undulation"?
"undulation" is spelled U-N-D-U-L-A-T-I-O-N.
What does "undulation" mean?
As a noun, "undulation" means: An instance or act of undulating.
What is the origin of the word "undulation"?
From undulate + -ion, or borrowed from Medieval Latin undulātiō; compare French ondulation. 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 “undulation”

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

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