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rust

(rŭst)

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

v.intr.

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.

v.tr.

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 the Appendix of Indo-European roots.]

rust adj.

rusta·ble adj.

Indo-European & Semitic Roots Appendices

Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

Indo-European Roots

Semitic Roots

The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.

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