rust

noun \ ˈrəst \

|Updated on: 12 Jul 2018

Definition of rust

1 a : the reddish brittle coating formed on iron especially when chemically attacked by moist air and composed essentially of hydrated ferric oxide

b : a comparable coating produced on a metal other than iron by corrosion

c : something resembling rust : accretion

2 : corrosive or injurious influence or effect

3 : any of numerous destructive diseases of plants produced by fungi (order Uredinales) and characterized by usually reddish-brown pustular lesions; also : a fungus causing this

4 : a strong reddish brown

See rust defined for English-language learners

See rust defined for kids

Examples of rust in a Sentence

an old pump covered in rust

Recent Examples of rust from the Web

The rest of the car wears a heavy patina and a fair amount of corrosion, but the bodywork and glass are in good shape and the only real rust issue can be found on one of the B-pillars.

— gary gastelu, Fox News, "1963 Chevrolet Corvette parked in a garage for 45 years could be worth a small fortune," 16 June 2018
Streaks of red and copper rust from their chains flow down their bodies, like blood.

— linda matchan, BostonGlobe.com, "A sculpture’s trans-Atlantic passage from Ghana to Alabama," 31 May 2018
The brakes will usually vibrate until the surface rust is worn off from several brake applications.

— bob weber, chicagotribune.com, "How could a newer car fail emissions testing?," 29 Apr. 2018
Fighters returning from lengthy absences often prefer a tuneup appearance and the proverbial steppingstone to help shake off possible ring rust.

— santos a. perez, miamiherald, "He hasn't fought in two years. Now he has the opportunity of a lifetime in comeback match | Miami Herald," 29 Apr. 2018
Scraping the rust off in a short time will be one thing for Porter and MU.

— vahe gregorian, kansascity, "Does Mizzou have enough time to develop chemistry with Michael Porter Jr.? | The Kansas City Star," 8 Mar. 2018
Remove stubborn rust from small tools with fine steel wool.

— cindy daniel, Sunset, "How to Maintan Your Garden Tools," 22 Jan. 2018
But through 12 innings, Whitley showed no signs of rust.

— carter karels, San Antonio Express-News, "Corpus Christi shuts out Missions," 18 June 2018
There might have been a bit of rust on the Sixers’ wheels.

— marcus hayes, Philly.com, "Sixers lose to Celtics but renew their rivalry | Marcus Hayes," 30 Apr. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'rust.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Origin and Etymology of rust

Middle English, from Old English rūst; akin to Old English rēad red — more at red

NEW! Time Traveler

First Known Use: before 12th century

in the meaning defined at sense 1a

See Words from the same year

rust

verb

Definition of rust

rusted; rusting; rusts

intransitive verb

1 : to form rust : become oxidized

iron rusts

2 : to degenerate especially from inaction, lack of use, or passage of time

most men would … have allowed their faculties to rust
—T. B. Macaulay

3 : to become reddish brown as if with rust

the leaves slowly rusted

4 : to be affected with a rust fungus

transitive verb

1 : to cause (a metal) to form rust

keep up your bright swords, for the dew will rust them
—William Shakespeare

2 : to impair or corrode by or as if by time, inactivity, or deleterious use

3 : to cause to become reddish brown : turn the color of rust

See rust defined for English-language learners

Examples of rust in a Sentence

Your bicycle will rust if you leave it out in the rain.
The moist air rusted the latch on the door.
The old iron fence was rusted.

Recent Examples of rust from the Web

But the pieces had sat out in the rain at the side of the highway for several days and had rusted.

— meg jones, Milwaukee Journal Sentinel, "Nightmare #1: Husband's death by flying debris on I-94. Nightmare #2: The investigation," 29 June 2018
Out front is one long unbroken run of rusting metal grates, beat-up signs, and decaying paint, while the area around back is littered with crushed beer cans, pillows, women’s lingerie, and signs of squatters.

— alex gailey, BostonGlobe.com, "Battered storefronts undermine progress at Dudley Square," 25 June 2018
There’s still rust on Serena’s game, the competition is quickly improving and, despite being a three-time champion of the event, the French Open has been her worst major.

— chris chase, For The Win, "Serena Williams has already won the French Open," 31 May 2018
Part of de-rusting yourself in the dating scene means going out of your comfort zone and trying experiences that are new and strange and maybe even terrifying.

— anna pulley, RedEye Chicago, "Ask Anna: Where do I meet single lesbians when I’m in my 40s?," 5 June 2017
Why: The awe-inspiring photo opportunities amid the rusted-saw peaks of the San Juan Mountains aren’t the only reason the 550 is called the Million Dollar Highway.

— latimes.com, "Detours worth taking on your next road trip," 20 May 2018
Officials have said the monument’s stone is shifting and its steel frame is rusting.

— scott huddleston, San Antonio Express-News, "Call sounded to keep Cenotaph in place," 17 May 2018
Its eerie, unearthly vibe—a landscape riddled with pits, and rusted-out cars everywhere—was immortalized in 1985 by director George Miller, who shot part of Mad Max Beyond Thunderdome there.

— ken jennings, Condé Nast Traveler, "Inside Coober Pedy, Australia's Underground Town," 14 May 2018
Donors will be eligible for Target gift cards worth $25 for s mall pistols up to .38 caliber and any gun that is rusted or doesn't work; $50 for handguns and semi-automatic pistols that are .9mm to .45 caliber and $75.00 for shotguns and rifles.

— linda trischitta, Sun-Sentinel.com, "Gift cards for guns event Saturday in Fort Lauderdale," 9 May 2018

First Known Use of rust

13th century

in the meaning defined at intransitive sense 1

See Words from the same year

NEW! Time Traveler

RUST Defined for English Language Learners

rust

noun

Definition of rust for English Language Learners

: a reddish substance that forms on iron or some other metal usually when it comes in contact with moisture or air
: a disease that causes plants to develop reddish-brown spots
: a reddish-brown color

rust

verb

Definition of rust for English Language Learners

: to form rust : to become rusty
: to cause rust to form on (something)

RUST Defined for Kids

rust

noun \ ˈrəst \

Definition of rust for Students

1 : a reddish coating formed on metal (as iron) when it is exposed especially to moist air

2 : a plant disease caused by fungi that makes spots on plants

3 : a fungus that causes a rust

rust

verb

Definition of rust for Students

rusted; rusting

: to make or become rusty

Medical Dictionary

rust

noun \ ˈrəst \

medical Definition of rust

1 : the reddish brittle coating formed on iron especially when chemically attacked by moist air and composed essentially of hydrated ferric oxide

2 : any of numerous destructive diseases of plants produced by fungi (order Uredinales) and characterized by reddish brown pustular lesions; also : a fungus causing this