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

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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

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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

When the sun hits the smog enveloping Indonesian Borneo, it turns everything the colour of rust.

From BBC ● Oct. 20, 2026

“I’m very concerned about the possible corrosion, specifically rust, of all the hardware that holds the bridge together and that attaches the cables,” one participant said.

From Los Angeles Times ● Oct. 16, 2026

They could be from naturally occurring phenomena like wheat rust and weather or from human activity such as sustained global conflicts.

From The Wall Street Journal ● Aug. 28, 2026

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

As we get closer to town we pass multifamily dwellings and some outlying businesses—a gas station, a corner shop, a nursery stocked with flowers the colors of autumn leaves: rust and gold and crimson.

From "Orphan Train" by Christina Baker Kline

“It needs a ton of work—even plastic rusts in Key West.”

From The Wall Street Journal ● Jan. 8, 2026

The mineral cave decor — epsomite, mirabilite, sulfate — rusts into the ruddy orange of iron oxide, the deep black of manganese.

From Salon ● Oct. 7, 2023

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

But it’s not my worry if the summer is wet and the wheat rusts.

From Girl Alone by Anne Austin

Unlike most of the memorial-makers discussed in “Scattered Steel,” Ms. Ando chose to alter the rusted metal she received.

From The Wall Street Journal ● Sep. 10, 2026

"This is a Tour de France original bicycle," from 1979, the 73-year-old added, holding up a piece of a rusted frame.

From Barron's ● Aug. 20, 2026

But he also didn’t want to die an old man on a rusted prison cot.

From Salon ● Aug. 10, 2026

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

From Los Angeles Times ● Jul. 15, 2026

For a long time, I wandered aimlessly—past ruined parks, blasted statuary, vacant lots overgrown with weeds and collapsed apartment houses with rusted girders poking out of their sides like ribs.

From "The Secret History" by Donna Tartt

Every year, tens of thousands of birds glide over the rusting remains of one of the Mediterranean's largest saltworks, to rest in the rare paradise it left behind.

From Barron's ● Jul. 15, 2026

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

The largest structure, a six-story building with dozens of broken windows, is sealed shut with rusting metal grillwork.

From The Wall Street Journal ● May 6, 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

Set into the wall at the bottom of the steps was another light switch, metal and rusting.

From "Coraline" by Neil Gaiman

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Related Words

• decay
• deteriorate
• wither

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