Rusts

Part of speech: verb, noun

Pronunciation: /ɹʌsts/

Definitions

1. Undergoes a chemical reaction causing a reddish-brown coating on iron or steel due to exposure to moisture and oxygen
2. Develops a flaky, reddish surface by reaction of metals with air and water over time
3. Becomes covered with corrosion that appears as a rough, rusty layer formed from oxidation

Etymology: "Rusts" is simply the plural of "rust" (and the third-person singular of the verb), so the story belongs to the noun. Rust is an old Germanic word, shared across the family: German "Rost," Dutch "roest," Swedish "rost," and Danish "rust" all mean the same thing. Its ancestor, reconstructed as "*rustaz" in Proto-Germanic, was probably related to a much older root meaning "red," the colour of the reddish-brown crust that iron takes on as it oxidises. So the word began as a description of colour and appearance rather than of chemistry. Iron and steel were known long before anyone understood oxidation, and people simply named the reddish coating they saw forming on metal. The connection to "red" is still visible in the cognates, which is why the colour and the corrosion have stayed linked in the words for it across the languages. English received the word as "rust" in Old English, and the verb "to rust" developed later from the noun in Middle English. Its meaning has stayed close to the original, covering a metal surface with that reddish layer.

Synonyms: corrodes, oxidizes

Antonyms: protects, coats