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

The pair made a poor start against Ukraine's Kostyuk and American Stearns before shaking off what Serena called "a little rust" in the second set.

From BBC ● Aug. 18, 2026

It then reverses the process, turning the rust back into iron and breathing out oxygen to charge and discharge the battery.

From The Wall Street Journal ● Aug. 12, 2026

The battery takes in oxygen and converts iron to rust.

From The Wall Street Journal ● Aug. 12, 2026

There is still “a lot of rust to knock off,” during camp and the lead-up to the season, he said.

From Los Angeles Times ● Aug. 2, 2026

Perhaps the bar had forced iron rust under the skin and made a kind of tattoo.

From "East of Eden" by John Steinbeck

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

From The Wall Street Journal ● Jan. 8, 2026

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

Copper rusts by exposure to the air; but the partially-calcined surface adheres to the metal, as in the case of lead, and thus preserves it from farther corrosion.

From Heads of Lectures on a Course of Experimental Philosophy: Particularly Including Chemistry by Joseph Priestley

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

Its curved blade, chipped and rusted, with a gilded, possibly brass, hilt featuring a lion on the end, is too delicate to hold.

From BBC ● Aug. 11, 2026

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

From Salon ● Aug. 10, 2026

This time the question was gruffer, like gravel scraping along rusted metal.

From "Boy 2.0" by Tracey Baptiste

"These coins were rusting and expanding and were capable of pressing the whole column of rock above them, pushing them up," he told BBC Radio Foyle's North West Today programme.

From BBC ● Aug. 18, 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

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

From The Wall Street Journal ● Apr. 17, 2026

Now they are rusting monuments to Scotland's industrial past.

From BBC ● Feb. 16, 2026

As I lift Alan to the ground, a mild vibration shudders the twists of rusting steel poking from the massive slabs.

From "Without Refuge" by Jane Mitchell

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Related Words

• decay
• deteriorate
• wither

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