English word rust comes from Proto-Indo-European *h₁rewdʰ-, and later Proto-Germanic *rustaz (Rust.)
| Dictionary entry | Language | Definition |
|---|---|---|
| *h₁rewdʰ- | Proto-Indo-European (ine) | |
| *rudʰso- | Proto-Indo-European (ine) | |
| *rudʰ-s-tos- | Proto-Indo-European (ine) | |
| *rustaz | Proto-Germanic (gem-pro) | Rust. |
| rūst | Old English (ca. 450-1100) (ang) | |
| rost | Middle English (1100-1500) (enm) | |
| rust | English (en) | A disease of plants caused by a reddish-brown fungus.. A reddish-brown color.. A similar substance based on another metal (usually with qualification, such as "copper rust").. The deteriorated state of iron or steel as a result of moisture and oxidation. (figuratively) To degenerate in idleness; to become dull or impaired by inaction.. (intransitive) To be affected with the parasitic fungus [...] |