casein
/ˈkeɪ.siːn/
"casein" is a 6-letter English headword indexed on PlainSpell.
The verdict
“casein” is uncommon English (frequency #50,416 among 5,599 “C” headwords), classed as a noun. The kind of spelling people second-guess.
- #50,416
- frequency rank, English
- 5,599
- “C” headwords
According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - A protein present in both milk and in the seeds of leguminous plants.
Corpus desk
Index EN-casein · casein · English
casein · rank #50,416 · 0 variants · 0 confusables
- FREQ-RARE #50,416
- LEN-LONG 6 letters
- VOW-3 3 vowels
- CONFUS-0 No pairs
- VAR-0 0 variants
- BOOK-DENSE 5,599
- PHOTO-FINISH casted
Nearest frequency peer: casted (+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 “casein”
Sparse band: bars invert rank so rarer forms read shorter
- Cait
Cait
49,590 corpus weight
- Caius
Caius
49,589 corpus weight
- calender
calender
49,588 corpus weight
- casein
casein
49,585 corpus weight
- casted
casted
49,583 corpus weight
- CFTC
CFTC
49,581 corpus weight
What this shows Long-tail view: where “casein” sits against similarly uncommon English ranks.
| Property | Value |
|---|---|
| Headword | casein |
| Language | English |
| Part of speech | Noun |
| IPA | /ˈkeɪ.siːn/ |
| Letters | 6 |
| Frequency rank | #50,416 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Long-tail rank of “casein” in English
Rare enough to double-check
casein is uncommon English at frequency #50,416 among 5,599 “C” headwords, classed as anoun, transcribed /ˈkeɪ.siːn/. Rarity is why readers land here mid-draft. Gloss: "A protein present in both milk and in the seeds of leguminous plants.".
The misspelling generator found no plausible variants for casein, typically a sign the spelling maps closely to how the word sounds. Our confusable-pair dataset has no match for it, since nothing in our dataset looks or sounds close enough to cause mix-ups.
Etymologically, the entry records: From French caséine, formed from Latin cāseus (“cheese”) + -ine. The correct English form is casein, spelled C-A-S-E-I-N.
Definition
- 1A protein present in both milk and in the seeds of leguminous plants.
Recorded use
Wiktionary examplesThese source excerpts show how casein appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.
Since writing this report, we found that the intravenous injection of nucleoprotein, casein, and probably also other albuminous substances may produce small necroses of liver tissue in the guinea pig. This observation points to a possible danger in the use of casein solutions."
It’s the clumping nature of the caseins that makes possible most thickened milk products, from yogurt to cheese. The whey proteins play a more minor role; they influence the texture of casein curds, and stabilize the milk foams on specialty coffees.
Etymology
From French caséine, formed from Latin cāseus (“cheese”) + -ine.
Synonyms
This word in other languages
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 "casein", not the corpus desk frequency band.
Same letter count
Frequency-ranked English headwords with 6 letters (nearest by frequency rank).