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[ruhst] /rʌst/
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.
any film or coating on metal caused by oxidation.
a stain resembling this coating.
any growth, habit, influence, or agency tending to injure, deteriorate, or impair the mind, character, abilities, usefulness, etc.
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.
reddish yellow, reddish brown, or yellowish red.
verb (used without object)
to become or grow rusty, as iron.
to contract rust.
to deteriorate or become impaired, as through inaction or disuse.
to become rust-colored.
verb (used with object)
to affect with rust.
to impair as if with rust.
to make rust-colored.
having the color rust.
Verb phrases
rust out, (of metal pipes, machinery, etc.) to decay and become unusable through the action of rust.
rust through, to develop holes, breaks, or the like, because of rust.
rust together, to join two metal pieces, as iron pipes, by causing the joint to rust.
before 900; (noun) Middle English; Old English rūst; cognate with German Rost; (v.) Middle English rusten, derivative of the noun; akin to red
Related forms
derust, verb (used with object)
unrust, verb (used with object)
2. corrosion. 9. decay, decline. Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the web for rust
  • If the pipes are made of a metal that will not rust or corrode, the pipes will last for many years.
  • Oil also helps to keep engine surfaces clean, makes start-up easier, and limits rust and corrosion.
  • Now it was a derelict, old and crippled, its bulkheads stained with patches of rust that could have been lesions.
  • There was loveliness to rust, cracks in the road, and a texture to the rocky sidewalks.
  • Blooms start out blush-colored, aging to coppery pink, then rust as weather cools.
  • Dense flower clusters start out blush pink, then age to rust as the weather cools.
  • They don't rust, are light and easily removed when repotting.
  • The leaves can gunk up the fan mechanism and snow that turns to ice can cause problems with either rust or expansion.
  • From the closet he takes an old white shirt, its shoulders tan with coat-hanger rust, with years.
  • Today rust-resistant varieties have been bred, and the berries are being revived.
British Dictionary definitions for rust


a reddish-brown oxide coating formed on iron or steel by the action of oxygen and moisture
(plant pathol) Also called rust fungus
  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
  1. a strong brown colour, sometimes with a reddish or yellowish tinge
  2. (as adjective): a rust carpet
any corrosive or debilitating influence, esp lack of use
to become or cause to become coated with a layer of rust
to deteriorate or cause to deteriorate through some debilitating influence or lack of use: he allowed his talent to rust over the years
Derived Forms
rustless, adjective
Word Origin
Old English rūst; related to Old Saxon, Old High German rost
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for rust

"red oxide of iron," Old English rust "rust; moral canker," related to rudu "redness," from Proto-Germanic *rusta- (cf. Frisian rust, Old High German and German rost, Middle Dutch ro(e)st), from PIE *reudh-s-to- (cf. Lithuanian rustas "brownish," rudeti "to rust;" Latin robigo, Old Church Slavonic ruzda "rust"), from root *reudh- "red" (see red (adj.1)).

As a plant disease, attested from mid-14c. Rust Belt "decayed urban industrial areas of mid-central U.S." (1984) was popularized, if not coined, by Walter Mondale's presidential campaign.


early 13c., from rust (n.). Transitive sense "cause to rust" is from 1590s. Related: Rusted; rusting.

Online Etymology Dictionary, © 2010 Douglas Harper
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rust in Medicine

rust (rŭst)
Any of a group of parasitic fungi of the order Uredinales that are plant pathogens, especially of cereal grains, and that can produce allergy in humans when inhaled in large numbers.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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rust in Science
  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.

    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.

Verb  To become corroded or oxidized.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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Related Abbreviations for rust


Remote User Scheduling Terminal
The American Heritage® Abbreviations Dictionary, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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Encyclopedia Article for rust

disease of thousands of economically important plants, as well as weeds, caused by more than 4,000 species of fungi.

Learn more about rust with a free trial on
Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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