rust

/ɹʌst/

//ɹʌst// noun

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

"rust" is a 4-letter English headword indexed on PlainSpell.

The verdict

“rust” is a moderately-common English word, ranked #10,604 in English word frequency and used as a noun.

#10,604
frequency rank, English
4
letters
6
tracked misspellings
20
confusable pairs

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - The deteriorated state of iron or steel as a result of moisture and oxidation; it consists mostly of iron(III) oxide (ferric oxide) and iron(II) oxide (ferrous oxide).

Visual similarity to commonly confused words

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

rust vs rut
75% similar
rust vs ruth
50% similar
rust vs rusty
80% similar

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

Key facts for rust
PropertyValue
Headwordrust
LanguageEnglish
Part of speechNoun
IPA/ɹʌst/
Letters4
Frequency rank#10,604
Misspellings tracked6
Confusable pairs20
SourceWiktionary (kaikki.org)

Where “rust” 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). rust lands here:

#1#100#1K#10K#100K
← used constantlyrarely used →

Scale is logarithmic (each tick is 10× rarer). Source: FrequencyWords open word-frequency list.

Spelling & Dictionary Insight

The English entry for rust is 4 letters long, classified as a noun, and transcribed in the International Phonetic Alphabet as /ɹʌst/. Corpus data places it at rank #10,604 in overall English word frequency, marking it as uncommon enough that many writers pause before typing it. Wiktionary records 5 distinct senses for this headword, so context determines which meaning a reader should apply.

Our generated misspelling index lists 6 likely wrong-spelling variants for rust, with forms such as "rrust", "rsut", and "russt". Each variant is a distinct typo pattern an edit-distance generator flags, typically a doubled-consonant error, a silent-letter drop, or a vowel substitution. It also participates in 20 confusable-pair relationships, "rut", "ruth", "rusty", and more, where similar look or sound leads writers to substitute one word for another in context.

Etymologically, the entry records: From Middle English rust, rost, roust, from Old English rust, rūst (“rust”), from Proto-West Germanic *rust, from Proto-Germanic *rustaz (“rust”), from Proto-Indo-European *rudʰso- (“red”), from Proto-Indo-European *h₁rewdʰ- (“red”). Cognate with Scots rous… The correct English form is rust, spelled R-U-S-T.

Definition

  1. 1
    The deteriorated state of iron or steel as a result of moisture and oxidation; it consists mostly of iron(III) oxide (ferric oxide) and iron(II) oxide (ferrous oxide).
  2. 2
    A similar substance based on another metal.
  3. 3
    A reddish-brown color.
  4. 4
    A disease of plants caused by a reddish-brown fungus (Pucciniales).
  5. 5
    Damage caused to stamps and album pages by a fungal infection.

Etymology

From Middle English rust, rost, roust, from Old English rust, rūst (“rust”), from Proto-West Germanic *rust, from Proto-Germanic *rustaz (“rust”), from Proto-Indo-European *rudʰso- (“red”), from Proto-Indo-European *h₁rewdʰ- (“red”). Cognate with Scots roust (“rust”), Saterland Frisian rust (“rust”), West Frisian roast (“rust”), Dutch roest (“rust”), German Rost (“rust”), Danish rust (“rust”), Swedish rost (“rust”), Norwegian rust, ryst (“rust”), Finnish ruoste, Estonian rooste. Related to red.

This word in other languages

óxido(Español)rouille(Français)Rost(Deutsch)ferrugem(Português)

Common misspellings

Also misspelled as: rrust,rsut,russt,rustt,ruts,urst

Misspelling Pattern Breakdown

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

rrust1rsut2russt1rustt1ruts2urst2
Edit distance from "rust"

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 "rust"?
"rust" is spelled R-U-S-T. The IPA pronunciation is /ɹʌst/.
What does "rust" mean?
As a noun, "rust" means: The deteriorated state of iron or steel as a result of moisture and oxidation; it consists mostly of iron(III) oxide (ferric oxide) and iron(II) oxide (ferrous oxide).
What words are commonly confused with "rust"?
"rust" is commonly confused with "rut", "ruth", "rusty". These words look or sound similar but have different meanings. PlainSpell provides detailed comparisons for each pair.
How do you pronounce "rust"?
The IPA (International Phonetic Alphabet) transcription for "rust" is /ɹʌst/. 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 "rust"?
From Middle English rust, rost, roust, from Old English rust, rūst (“rust”), from Proto-West Germanic *rust, from Proto-Germanic *rustaz (“rust”), from Proto-Indo-European *rudʰso- (“red”), from Proto-Indo-European *h₁rewdʰ- (“red”). Cognate with ... 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 “rust”

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

  • The one correct English spelling is R-U-S-T - every other letter order is a misspelling in standard orthography.
  • Say it as /ɹʌst/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
  • Don't mix it up with “rut” - see the side-by-side comparison. rust vs rut
  • Browse more English words and confusable pairs in the same reference. English words
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.

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

Source: FrequencyWords open word-frequency list FrequencyWords open word-frequency list