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 5,599 “C” headwords), classed as a noun. The kind of spelling people second-guess.

#80,285
frequency rank, English
5,599
“C” headwords

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - An enclosure from which water can be expelled, in order to give access to underwater areas for engineering works etc.

Corpus desk

Index EN-caisson · caisson · English

caisson · rank #80,285 · 0 variants · 0 confusables

  • FREQ-RARE #80,285
  • LEN-LONG 7 letters
  • VOW-3 3 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-DENSE 5,599
  • PHOTO-FINISH Caffrey

Nearest frequency peer: Caffrey (-1 rank slots)

Read with this headword: Spelling guide for this pattern

Desk codes from Wiktionary headword shape, FrequencyWords rank tier, confusable-pair count, generated misspelling depth, letter-cohort book size, and photo-finish peer. Not a difficulty grade.

Long-tail ranks near “caisson”

Sparse band: bars invert rank so rarer forms read shorter

corpus weight

What this shows Long-tail view: where “caisson” sits against similarly uncommon English ranks.

Source FrequencyWords open word-frequency list As of September 3, 2026
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)

Long-tail rank of “caisson” in English

Word frequency stretches from the small set of words we reach for constantly (left) out to the long tail barely used once in a while (right).caissonfalls in this rarity band:

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

Ticks step logarithmically, so each one marks a roughly tenfold drop in how often the word turns up. Rare peers in the same band: “Caffrey” (#80,284), “callously” (#80,287), “camas” (#80,288). Among 5,599 “C” headwords, “caisson” is #80,285. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

caisson is uncommon English at frequency #80,285 among 5,599 “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.

Recorded use

Wiktionary examples

These source excerpts show how caisson appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.

  1. During the construction of the viaduct, the sinking of the caissons in the river bed caused much difficulty to the engineer and contractors, as a bed of running sand was encountered; in consequence, the expenditure for these foundations proved almost prohibitive.
  2. Caissons were enclosed dry chambers built on river beds to facilitate the construction of bridge piers.

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.

Similar English words by spelling shape

Same letter count and similar misspelling depth for "caisson", not the corpus desk frequency band.

Same letter count

Frequency-ranked English headwords with 7 letters (nearest by frequency rank).

Caffrey#80,284carwash#80,300brekkie#80,269breccia#80,268

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

Source: FrequencyWords open word-frequency list