caisson

/ˈkeɪ.sən/

//ˈkeɪ.sən// noun

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

"caisson" is a 7-letter English headword indexed on PlainSpell.

The verdict

“caisson” is uncommon English (frequency #80,285 among 43,570 “C” headwords), classed as a noun. The kind of spelling people second-guess.

#80,285
frequency rank, English
43,570
“C” headwords

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - An enclosure from which water can be expelled, in order to give access to underwater areas for engineering works etc.

Key facts for caisson
PropertyValue
Headwordcaisson
LanguageEnglish
Part of speechNoun
IPA/ˈkeɪ.sən/
Letters7
Frequency rank#80,285
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Where “caisson” 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). caisson 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

caisson is uncommon English at frequency #80,285 among 43,570 “C” headwords, classed as anoun, transcribed /ˈkeɪ.sən/. Rarity is why readers land here mid-draft. 7 senses are on record.

No generated misspelling entries exist for caisson in our index, a straightforward case of a spelling with little room for common typos. Our confusable-pair dataset has no match for it, which typically means the spelling is too distinctive to be mistaken for another word.

Etymologically, the entry records: Borrowed from French caisson. Doublet of cassone and cajón. The correct English form is caisson, spelled C-A-I-S-S-O-N.

Definition

  1. 1
    An enclosure from which water can be expelled, in order to give access to underwater areas for engineering works etc.
  2. 2
    The gate across the entrance to a dry dock.
  3. 3
    A floating tank that can be submerged, attached to an underwater object and then pumped out to lift the object by buoyancy; a camel.
  4. 4
    A two-wheeled, horse-drawn military vehicle used to carry ammunition (and a coffin at funerals).
  5. 5
    A large box to hold ammunition.
  6. 6
    A chest filled with explosive materials, used like a mine.
  7. 7
    A coffer.

Etymology

Borrowed from French caisson. Doublet of cassone and cajón.

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 "caisson"?
"caisson" is spelled C-A-I-S-S-O-N. The IPA pronunciation is /ˈkeɪ.sən/.
What does "caisson" mean?
As a noun, "caisson" means: An enclosure from which water can be expelled, in order to give access to underwater areas for engineering works etc.
How do you pronounce "caisson"?
The IPA (International Phonetic Alphabet) transcription for "caisson" is /ˈkeɪ.sən/. Click the speaker icon on the pronunciation badge above to hear it spoken aloud where audio is available.
What is the origin of the word "caisson"?
Borrowed from French caisson. Doublet of cassone and cajón. 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 “caisson”

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

  • The one correct English spelling is C-A-I-S-S-O-N - every other letter order is a misspelling in standard orthography.
  • Say it as /ˈkeɪ.sən/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
  • 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