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a. Any of various powdery or scaly reddish-brown or reddish-yellow hydrated ferric oxides and hydroxides formed on iron and iron-containing materials by low-temperature oxidation in the presence of water.
b. Any of various metallic coatings, especially oxides, formed by corrosion.
c. A stain or coating resembling iron rust.
2. Deterioration, as of ability, resulting from inactivity or neglect.
3. Botany
a. Rust fungus.
b. A plant disease caused by a rust fungus, characterized by reddish or brownish spots on leaves, stems, and other parts.
4. A strong brown.
v. rust·ed, rust·ing, rusts
1. To become corroded.
2. To deteriorate or degenerate through inactivity or neglect: My golf game has rusted from all those years of not playing.
3. To become the color of rust.
4. Botany To develop a disease caused by a rust fungus.
1. To corrode or subject (a metal) to rust formation.
2. To impair or spoil, as by misuse or inactivity.
3. To color (something) a strong brown.

[Middle English, from Old English rūst; see reudh- in Indo-European roots.]

rust adj.
rust′a·ble adj.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


liable to rust
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
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In packaging it has potential for protecting medical devices, pharmaceutical products, easily oxidisable and rustable materials and vacuum heat insulating building materials.
Of course, an efficient gardener would have given them a quick wipe over with a cloth at the back end of the year - but what usually happens in December is a quick blast of WD 40 on anything that looks rustable and into the shed.
Among these were the plastic brick tie, replacing the rustable metal figure of eight ties which litter building sites across the land.