operculum

Name: operculum, English Word Data
Creator: Wiktionary
License: https://creativecommons.org/licenses/by-sa/4.0/

/əʊˈpɜː.kjʊ.ləm/

//əʊˈpɜː.kjʊ.ləm// noun

By PlainSpell · According to Wiktionary data (CC BY-SA) · analyzed May 6, 2026

The verdict

“operculum” is uncommon English (frequency #77,980 among 15,494 “O” headwords), classed as a noun. The kind of spelling people second-guess.

#77,980
frequency rank, English: 15,494
“O” headwords

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - A covering flap in animals, such as a gill cover.

Key facts for operculum
Property	Value
Headword	operculum
Language	English
Part of speech	Noun
IPA	/əʊˈpɜː.kjʊ.ləm/
Letters	9
Frequency rank	#77,980
Misspellings tracked	0
Confusable pairs	0
Source	Wiktionary (kaikki.org)

Where “operculum” 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). operculum lands here:

#77,980

#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

operculum is uncommon English at frequency #77,980 among 15,494 “O” headwords, classed as anoun, transcribed /əʊˈpɜː.kjʊ.ləm/. Rarity is why readers land here mid-draft. 5 senses are on record.

operculum doesn't appear in our generated misspelling index, and the word's spelling is regular enough that our generator found nothing worth flagging. It is not paired with a close-neighbour confusable in our dataset, since no other headword is close enough in sound or shape to pair with it.

Etymologically, the entry records: Borrowed from Latin operculum. The correct English form is operculum, spelled O-P-E-R-C-U-L-U-M.

Definition

1
A covering flap in animals, such as a gill cover.
2
The lidlike portion of a moss sporangium or of a fruit that detaches to allow the dispersal of spores or seeds.
3
A gum flap covering (part of) a partially erupted tooth, usually a wisdom tooth.
4
A structure which serves as a cover or lid.
5
One of several flaps of cerebral cortex covering the insula.

Etymology

Borrowed from Latin operculum.

This word in other languages

opérculo(Español)opercule(Français)

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 "operculum"?

"operculum" is spelled O-P-E-R-C-U-L-U-M. The IPA pronunciation is /əʊˈpɜː.kjʊ.ləm/.

What does "operculum" mean?

As a noun, "operculum" means: A covering flap in animals, such as a gill cover.

How do you pronounce "operculum"?

The IPA (International Phonetic Alphabet) transcription for "operculum" is /əʊˈpɜː.kjʊ.ləm/. 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 "operculum"?

Borrowed from Latin operculum. 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 “operculum”

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

The one correct English spelling is O-P-E-R-C-U-L-U-M - every other letter order is a misspelling in standard orthography.
Say it as /əʊˈpɜː.kjʊ.ləm/ (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.