capsule

/ˈkæps(ə)l/

//ˈkæps(ə)l// noun

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

The verdict

“capsule” is a moderately-common English word, ranked #11,176 in English word frequency and used as a noun.

#11,176
frequency rank, English
7
letters
10
tracked misspellings
3
confusable pairs

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - A membranous envelope.

Visual similarity to commonly confused words

How many letter changes separate each confused pair (Levenshtein distance, normalized).

capsule vs castle
71% similar
capsule vs capture
71% similar
capsule vs capable
71% similar

Source: PlainSpell confusable corpus (Wiktionary, CC BY-SA).

Key facts for capsule
PropertyValue
Headwordcapsule
LanguageEnglish
Part of speechNoun
IPA/ˈkæps(ə)l/
Letters7
Frequency rank#11,176
Misspellings tracked10
Confusable pairs3
SourceWiktionary (kaikki.org)

Where “capsule” 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). capsule lands here:

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

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

Spelling & Dictionary Insight

The English entry for capsule is 7 letters long, classified as a noun, and transcribed in the International Phonetic Alphabet as /ˈkæps(ə)l/. Corpus data places it at rank #11,176 in overall English word frequency, marking it as uncommon enough that many writers pause before typing it. Wiktionary records 13 distinct senses for this headword, so context determines which meaning a reader should apply.

Our generated misspelling index lists 10 likely wrong-spelling variants for capsule, with forms such as "acpsule", "cappsule", and "capslue". Each of these forms differs from the correct spelling by one small edit: a doubled letter, a dropped silent letter, or a substituted vowel. It also participates in 3 confusable-pair relationships, "castle", "capture", "capable", since the words sound or look close enough that writers reach for the wrong one mid-sentence.

Etymologically, the entry records: Borrowed from French capsule, from Latin capsula, diminutive of capsa (“box”). The correct English form is capsule, spelled C-A-P-S-U-L-E.

Definition

  1. 1
    A membranous envelope.
  2. 2
    A type of simple, dehiscent, dry fruit (seed-case) produced by many species of flowering plants, such as poppy, lily, orchid, willow and cotton.
  3. 3
    A sporangium, especially in bryophytes.
  4. 4
    A tough, fibrous layer surrounding an organ such as the kidney or liver
  5. 5
    A membrane that surrounds the eyeball
  6. 6
    A detachable part of a rocket or spacecraft (usually in the nose) containing the crew's living space.
  7. 7
    A small container containing a dose of medicine.
  8. 8
    in a brief, condensed or compact form
  9. 9
    The covering — formerly lead or tin, now often plastic — over the cork at the top of the wine bottle.
  10. 10
    A small clay saucer for roasting or melting samples of ores, etc.; a scorifier.
  11. 11
    A small, shallow evaporating dish, usually of porcelain.
  12. 12
    A small cup or shell, often of metal, for a percussion cap, cartridge, etc.
  13. 13
    One of the very small rooms for guests in a capsule hotel.

Etymology

Borrowed from French capsule, from Latin capsula, diminutive of capsa (“box”).

This word in other languages

Common misspellings

Also misspelled as: acpsule,cappsule,capslue,capssule,capsuel,capsulle,capusle,caspule,ccapsule,cpasule

Misspelling Pattern Breakdown

How far each generated variant is from the correct spelling of capsule - expressed in single-character edits (insert, delete, or swap one letter). Bigger bars stand out at a glance; a one-edit slip is the hardest to catch.

acpsule2cappsule1capslue2capssule1capsuel2capsulle1capusle2caspule2
Edit distance from "capsule"

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 "capsule"?
"capsule" is spelled C-A-P-S-U-L-E. The IPA pronunciation is /ˈkæps(ə)l/.
What does "capsule" mean?
As a noun, "capsule" means: A membranous envelope.
What words are commonly confused with "capsule"?
"capsule" is commonly confused with "castle", "capture", "capable". These words look or sound similar but have different meanings. PlainSpell provides detailed comparisons for each pair.
How do you pronounce "capsule"?
The IPA (International Phonetic Alphabet) transcription for "capsule" is /ˈkæps(ə)l/. 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 "capsule"?
Borrowed from French capsule, from Latin capsula, diminutive of capsa (“box”). 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 “capsule”

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

  • The one correct English spelling is C-A-P-S-U-L-E - every other letter order is a misspelling in standard orthography.
  • Say it as /ˈkæps(ə)l/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
  • Don't mix it up with “castle” - see the side-by-side comparison. capsule vs castle
  • 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 FrequencyWords open word-frequency list