Aeruginous

Part of speech: adjective

Definitions

1. Having a color that is often described as greenish-blue, which is typically found on oxidized metals like copper
2. Relating to a hue that appears similar to tarnished copper, indicative of oxidation or corrosion
3. Characterized by a bluish-green tint reminiscent of oxidized metal surfaces, particularly copper, which reflects the effects of corrosion

Etymology: Copper's green coating has been called by its own name for centuries, and this adjective grows straight out of that name. Latin "aerugo" meant rust, and in its original sense it referred to the crust that forms on copper and bronze, which is why the Latin word is built on "aes," meaning copper, bronze or brass. The suffix "-ōsus" simply turns a noun into an adjective meaning "full of" or "characterised by," so "aeruginosus" meant something like "full of copper rust." The word reached English through two routes. Medieval Latin writers used "aeruginosus" directly, while French speakers took the same stem and shaped it into "erugineux," meaning "verdigris-coloured." The English adjective draws on both traditions, so it carries the Latin sense of rust together with the French association with the bluish-green patina that copper develops.

Synonyms: verdigris, greenish-blue, bluish-green