rust

American  

[ruhst] / rʌst /

noun

• rust
  plural

1. Also called iron rust. the red or orange coating that forms on the surface of iron when exposed to air and moisture, consisting chiefly of ferric hydroxide and ferric oxide formed by oxidation.

2. any film or coating on metal caused by oxidation.

   Synonyms:

   corrosion

3. a stain resembling this coating.

4. any growth, habit, influence, or agency tending to injure, deteriorate, or impair the mind, character, abilities, usefulness, etc.

5. Plant Pathology.

   1. any of several diseases of plants, characterized by reddish, brownish, or black pustules on the leaves, stems, etc., caused by fungi of the order Uredinales.

   2. Also called rust fungus. a fungus causing this disease.

   3. any of several other diseases of unknown cause, characterized by reddish-brown spots or discolorations on the affected parts.

6. reddish yellow, reddish brown, or yellowish red.

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verb (used without object)

• rusts,
  present (3rd person singular)
• rusted,
  past participle,  past
• rusting
  present participle

1. to become or grow rusty, as iron.

2. to contract rust.

3. to deteriorate or become impaired, as through inaction or disuse.

   Synonyms:

   decline, decay

4. to become rust-colored.

verb (used with object)

• rusts,
  present (3rd person singular)
• rusted,
  past participle,  past
• rusting
  present participle

1. to affect with rust.

2. to impair as if with rust.

3. to make rust-colored.

adjective

1. having the color rust.

verb phrase

1. rust out (of metal pipes, machinery, etc.) to decay and become unusable through the action of rust.

2. rust together to join two metal pieces, as iron pipes, by causing the joint to rust.

3. rust through to develop holes, breaks, or the like, because of rust.

rust British  

/ rʌst /

noun

1. a reddish-brown oxide coating formed on iron or steel by the action of oxygen and moisture

2. Also called: rust fungus. plant pathol

   1. any basidiomycetous fungus of the order Uredinales , parasitic on cereal plants, conifers, etc

   2. any of various plant diseases characterized by reddish-brown discoloration of the leaves and stem, esp that caused by the rust fungi

3. 1. a strong brown colour, sometimes with a reddish or yellowish tinge

   2. ( as adjective )

      a rust carpet

4. any corrosive or debilitating influence, esp lack of use

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verb

1. to become or cause to become coated with a layer of rust

2. to deteriorate or cause to deteriorate through some debilitating influence or lack of use

   he allowed his talent to rust over the years

rust Scientific  

/ rŭst /

1. Any of the various reddish-brown oxides of iron that form on iron and many of its alloys when they are exposed to oxygen in the presence of moisture.

2. 1. Any of various basidiomycete fungi that are parasitic on plants and produce reddish or brownish spots on leaves. Rusts attack a wide variety of plants and can cause enormous damage to crops.

   2. Any of the various plant diseases caused by these fungi.

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1. To become corroded or oxidized.

Other Word Forms

Derived Forms

• derust
  verb (used with object)
• unrust
  verb (used with object)
• rustless
  adjective

Inflected Forms

Nouns

• rust
  plural

Participles

• rusting
  present
• rusted
  past

Conjugated Forms

Present

• rust
  simple
• rusts
  simple
• have rusted
  perfect
• has rusted
  perfect
• am rusting
  progressive
• are rusting
  progressive
• is rusting
  progressive
• have been rusting
  perfect progressive
• has been rusting
  perfect progressive

Past

• rusted
  simple
• had rusted
  perfect
• was rusting
  progressive
• were rusting
  progressive
• had been rusting
  perfect progressive

Future

• will rust
  simple
• will have rusted
  perfect
• will be rusting
  progressive
• will have been rusting
  perfect progressive

Etymology

Origin of rust

before 900; (noun) Middle English; Old English rūst; cognate with German Rost; (v.) Middle English rusten, derivative of the noun; akin to red ¹

Explanation

Rust is the reddish-brown stuff that forms over time on metal that's gotten wet. Your dad's beat-up old car probably has some rust on it somewhere. If you leave your bike out overnight in the rain, it'll be fine — you can dry it off the next day. If you leave it out for several rainy weeks, though, your bike will end up with rust on it. Rust appears as brown spots where the combination of water and oxygen has coated the metal with a compound that chemists call an oxide. Rust, which is also a verb, comes from a Germanic root meaning "redness."

Example Sentences

See Examples For:

rust rusts rusted rusting

The 59-year-old zoo, which occupies 133 acres in the northeast corner of Griffith Park, has also struggled to maintain its national accreditation, with federal regulators finding peeling paint and rust in some exhibits.

From Los Angeles Times ● Jul. 31, 2026

For Joshua, it is about far more than shaking off ring rust.

From BBC ● Jul. 24, 2026

We just have to shake off a little rust first.

From Slate ● Jul. 20, 2026

As part of his reporting, he had a Chinese-made MG4 inspected after three Finnish winters and 80,000 kilometers, checking for underbody rust and wear, and found little to complain about.

From The Wall Street Journal ● Jul. 7, 2026

The sun burnt Tristran's face to a nut-brown color and faded his clothes to the hues of rust and of dust.

From "Stardust" by Neil Gaiman

Carbon steel gives a sharper edge than stainless steel, and it’s easier to sharpen, but the blade rusts easily.

From The Wall Street Journal ● Nov. 23, 2025

Carbon steel rusts easily, so those knives have to be consistently washed and dried to avoid discoloration.

From Washington Times ● Jun. 9, 2023

Fungal rusts and smuts that are proliferating in our increasingly warmer and wetter world endanger the world’s coffee supply.

From Washington Post ● Jul. 15, 2022

"Most ring pots are metal, which rusts and breaks down over time," he explained.

From Salon ● Jun. 19, 2021

It is the corrosive element that rusts away all the pure gold of energy and aspiration.

From The Universe a Vast Electric Organism by George Woodward Warder

Mercantile scales and rusted bird cages are scattered across crowded shelves.

From Los Angeles Times ● Jul. 15, 2026

Nobody knows how, since the bell’s been chained up for such a long time that the metal links have rusted.

From Salon ● Jun. 18, 2026

Fencing was rusted and laying on the ground, and the grass was waist high.

From The Wall Street Journal ● Jun. 7, 2026

While trimming back Valerie's hedges and clearing brambles, the 24-year-old spotted a rusted, 50cm device that looked "almost like a mortar stood up on its tail".

From BBC ● May 28, 2026

"I haven't had a stroopwafel in a while," I say finally, trying out my rusted conversational skills.

From "Girl in the Blue Coat" by Monica Hesse

Old and rusting tankers like these form what maritime experts call the “shadow fleet,” a roving armada of hundreds of vessels that ferry oil for sanctioned regimes, including Iran and Russia.

From The Wall Street Journal ● May 28, 2026

Today, abandoned barge cranes lie rusting and rotting in delta sloughs.

From The Wall Street Journal ● Apr. 17, 2026

The reef is home to a small Philippine military outpost aboard the BRP Sierra Madre, a rusting World War Two-era ship deliberately grounded there in 1999 to assert Manila's claim to the territory.

From BBC ● Apr. 13, 2026

Goodison-Blanks said the tin itself had some "patternation and rusting" on it and the label was a "bit worn".

From BBC ● Mar. 18, 2026

Later, at one of the round rusting metal tables in the comer of the warehouse that served as the lunch area, I found out more about my new writer friend.

From "Kindred" by Octavia Butler

Related Words

• decay
• deteriorate
• wither