protein

/ˈpɹəʊ.ti.ɪn/

//ˈpɹəʊ.ti.ɪn// noun

By · According to Wiktionary data (CC BY-SA) ·

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

The verdict

“protein” has 10 generated spelling variants in the English index at frequency #2,851. The variants make it a useful spelling check.

#2,851
frequency rank, English
4,417
“P” headwords
10
tracked misspellings
6
confusable pairs

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - Any of numerous large, complex naturally-produced molecules composed of one or more long chains of amino acids, in which the amino acid groups are held together by peptide bonds.

Corpus desk

Index EN-protein · protein · English

protein · rank #2,851 · 10 variants · 6 confusables

  • FREQ-COMMON #2,851
  • LEN-LONG 7 letters
  • VOW-3 3 vowels
  • CONFUS-MID 6 pairs
  • VAR-MID 10 variants
  • BOOK-MID 4,417
  • PHOTO-FINISH princess

Nearest frequency peer: princess (-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.

Rank peers near misspelling magnet “protein”

Same rarity band: useful when a typo lands on a peer headword

corpus weight

What this shows “protein” sits among these FrequencyWords peers; misspelling depth is tracked separately in the edit-distance chart.

Source FrequencyWords open word-frequency list As of September 3, 2026

Visual similarity to commonly confused words

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

protein vs proven
71% similar
protein vs proton
71% similar
protein vs protest
71% similar

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

Key facts for protein
PropertyValue
Headwordprotein
LanguageEnglish
Part of speechNoun
IPA/ˈpɹəʊ.ti.ɪn/
Letters7
Frequency rank#2,851
Misspellings tracked10
Confusable pairs6
SourceWiktionary (kaikki.org)

Frequency seat of misspelling magnet “protein”

Every-word frequency runs from the handful of words we use constantly (left) to the long tail used once in a blue moon (right).proteinlands here:

#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. Same rarity band neighbours include “princess” (#2,850), “puts” (#2,852), “pounds” (#2,849). Among 4,417 “P” headwords, “protein” is #2,851. Source: FrequencyWords open word-frequency list.

A misspelling magnet

The generator records 10 spelling variants around protein (IPA /ˈpɹəʊ.ti.ɪn/), anoun. Corpus frequency is #2,851 among 4,417 “P” headwords. Wiktionary lists 3 senses, so context still picks the gloss.

Our generated misspelling index lists 10 likely wrong-spelling variants for protein, with forms such as "portein", "pprotein", and "proetin". 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 6 confusable-pair relationships, "proven", "proton", "protest", and more, a pairing that trips writers up because the two words share enough sound or shape to blur together.

Etymologically, the entry records: From proto- + -ein. Suggested by Jöns Jacob Berzelius in a letter to Gerardus Johannes Mulder, from French protéine and German Protein, both coined based on Ancient Greek πρωτεῖος (prōteîos, “primary”), from πρῶτος (prôtos, “first”). The correct English form is protein, spelled P-R-O-T-E-I-N.

Definition

  1. 1
    Any of numerous large, complex naturally-produced molecules composed of one or more long chains of amino acids, in which the amino acid groups are held together by peptide bonds.
  2. 2
    One of three major classes of food or source of food energy (4 kcal/gram) abundant in animal-derived foods (meat) and some vegetables, such as legumes.
  3. 3
    A food rich in protein, often a meat or meat substitute.

Recorded use

Wiktionary examples

These source excerpts show how protein appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.

  1. Proteins carry out the bulk of cellular functions, including relaying signals, providing structural support, and accelerating biochemical reactions.
  2. Because of her significant testing, Avery had had DNA sequencing of her “exome,” the part of her genome that makes proteins in the body, said Dr. Michael Wangler, a researcher at the Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital.

Etymology

From proto- + -ein. Suggested by Jöns Jacob Berzelius in a letter to Gerardus Johannes Mulder, from French protéine and German Protein, both coined based on Ancient Greek πρωτεῖος (prōteîos, “primary”), from πρῶτος (prôtos, “first”).

Synonyms

protein

This word in other languages

proteína(Español)protéine(Français)Protein(Deutsch)

Common misspellings

Also misspelled as:

  • portein
  • pprotein
  • proetin
  • proteinn
  • proteni
  • protien
  • prottein
  • prrotein
  • prtoein
  • rpotein

Misspelling Pattern Breakdown

How far each generated variant is from the correct spelling of protein - measured in single-character edits (insert, delete, or substitute a letter). Larger bars are easier to catch; one-edit slips are the sneakiest.

portein2pprotein1proetin2proteinn1proteni2protien2prottein1prrotein1
Edit distance from "protein"

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 "protein"?
"protein" is spelled P-R-O-T-E-I-N. The IPA pronunciation is /ˈpɹəʊ.ti.ɪn/.
What does "protein" mean?
As a noun, "protein" means: Any of numerous large, complex naturally-produced molecules composed of one or more long chains of amino acids, in which the amino acid groups are held together by peptide bonds.
What words are commonly confused with "protein"?
"protein" is commonly confused with "proven", "proton", "protest". These words look or sound similar but have different meanings. PlainSpell provides detailed comparisons for each pair.
How do you pronounce "protein"?
The IPA (International Phonetic Alphabet) transcription for "protein" is /ˈpɹəʊ.ti.ɪn/. 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 "protein"?
From proto- + -ein. Suggested by Jöns Jacob Berzelius in a letter to Gerardus Johannes Mulder, from French protéine and German Protein, both coined based on Ancient Greek πρωτεῖος (prōteîos, “primary”), from πρῶτος (prôtos, “first”). 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 "protein", not the corpus desk frequency band.

Same letter count

Frequency-ranked English headwords with 7 letters (nearest by frequency rank).

portion#2,848regions#2,855respond#2,857letting#2,840

Similar misspelling depth

Headwords with a similar count of attested misspellings (10 here; floor ≥5).

princess10 variantsinvited10 variantssomehow10 variantsSydney10 variants

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

Source: FrequencyWords open word-frequency list