CLU

/kluː/

//kluː// name

"clu" is a 3-letter English headword indexed on PlainSpell.

The verdict

“CLU” is uncommon English (frequency #58,603 among 5,599 “C” headwords), classed as a proper noun. The kind of spelling people second-guess.

#58,603
frequency rank, English
5,599
“C” headwords

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - A computer language developed between 1973–1975 that pioneered abstract data types and iterators.

Corpus desk

Index EN-clu · CLU · English

CLU · rank #58,603 · 0 variants · 0 confusables

  • FREQ-RARE #58,603
  • LEN-MID 3 letters
  • VOW-1 1 vowel
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-DENSE 5,599
  • PHOTO-FINISH clotted

Nearest frequency peer: clotted (-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 “CLU”

Sparse band: bars invert rank so rarer forms read shorter

corpus weight

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

Source FrequencyWords open word-frequency list As of September 3, 2026
Key facts for CLU
PropertyValue
HeadwordCLU
LanguageEnglish
Part of speechProper noun
IPA/kluː/
Letters3
Frequency rank#58,603
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “CLU” in English

This scale runs from the tiny cluster of words that carry ordinary speech (left) to the long tail of words almost nobody reaches for (right).CLUfalls 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: “clotted” (#58,602), “coenzyme” (#58,604), “cloakroom” (#58,601). Among 5,599 “C” headwords, “CLU” is #58,603. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

CLU is uncommon English at frequency #58,603 among 5,599 “C” headwords, classed as aproper noun, transcribed /kluː/. Rarity is why readers land here mid-draft. Gloss: "A computer language developed between 1973–1975 that pioneered abstract data types and iterators.".

The misspelling generator found no plausible variants for CLU, suggesting the orthography follows predictable English patterns. It is not paired with a close-neighbour confusable in our dataset, which tends to mean the word is visually distinctive enough to stand on its own.

Etymologically, the entry records: Clipping of cluster, a concept equivalent to classes in object-oriented programming. The correct English form is CLU, spelled C-L-U.

Definition

  1. 1
    A computer language developed between 1973–1975 that pioneered abstract data types and iterators.

Etymology

Clipping of cluster, a concept equivalent to classes in object-oriented programming.

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 "CLU"?
"CLU" is spelled C-L-U. The IPA pronunciation is /kluː/.
What does "CLU" mean?
As a proper noun, "CLU" means: A computer language developed between 1973–1975 that pioneered abstract data types and iterators.
How do you pronounce "CLU"?
The IPA (International Phonetic Alphabet) transcription for "CLU" is /kluː/. 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 "CLU"?
Clipping of cluster, a concept equivalent to classes in object-oriented programming. 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 "CLU", not the corpus desk frequency band.

Same letter count

Frequency-ranked English headwords with 3 letters (nearest by frequency rank).

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

Source: FrequencyWords open word-frequency list