CFU
"cfu" is a 3-letter English headword indexed on PlainSpell.
The verdict
“CFU” is uncommon English (frequency #63,503 among 5,599 “C” headwords), classed as a noun. The kind of spelling people second-guess.
- #63,503
- frequency rank, English
- 5,599
- “C” headwords
According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - Initialism of colony-forming unit.
Corpus desk
Index EN-cfu · CFU · English
CFU · rank #63,503 · 0 variants · 0 confusables
- FREQ-RARE #63,503
- LEN-MID 3 letters
- VOW-1 1 vowel
- CONFUS-0 No pairs
- VAR-0 0 variants
- BOOK-DENSE 5,599
- PHOTO-FINISH CEI
Nearest frequency peer: CEI (-2 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 “CFU”
Sparse band: bars invert rank so rarer forms read shorter
- cassino
cassino
36,501 corpus weight
- CEI
CEI
36,500 corpus weight
- CFU
CFU
36,498 corpus weight
- chemtrails
chemtrails
36,496 corpus weight
- circumferen…
circumferential
36,494 corpus weight
- clandestine…
clandestinely
36,492 corpus weight
What this shows Long-tail view: where “CFU” sits against similarly uncommon English ranks.
| Property | Value |
|---|---|
| Headword | CFU |
| Language | English |
| Part of speech | Noun |
| Letters | 3 |
| Frequency rank | #63,503 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Long-tail rank of “CFU” in English
Rare enough to double-check
CFU is uncommon English at frequency #63,503 among 5,599 “C” headwords, classed as anoun. Rarity is why readers land here mid-draft. Gloss: "Initialism of colony-forming unit.".
No misspelling variants are generated for CFU in our index, since its letter pattern doesn't lend itself to common typo substitutions. No close-neighbour confusable shows up for this headword in our dataset, which usually means its spelling is distinct enough that readers don't reach for a similar-looking word instead.
This entry carries no recorded etymology, so spelling patterns must be inferred from the word's phoneme-to-grapheme mapping rather than from a documented borrowing chain. The correct English form is CFU, spelled C-F-U.
Definition
- 1Initialism of colony-forming unit.
Recorded use
Wiktionary exampleThese source excerpts show how CFU appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.
The three water samples for total coliform bacteria were 57,000 CFUs, 43,000 CFUs and 45,000 CFUs. (Colony-forming units, or CFUs, estimate the number of bacteria or fungal cells that have the ability to multiply in a sample.)
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
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Similar English words by spelling shape
Same letter count and similar misspelling depth for "CFU", not the corpus desk frequency band.
Same letter count
Frequency-ranked English headwords with 3 letters (nearest by frequency rank).