copper

(uncountable) A reddish-brown, malleable, ductile metallic element with high electrical and thermal conductivity, symbol Cu, and atomic number 29.

The reddish-brown colour/color of copper.

(countable) A copper coin, typically of a small denomination, such as a penny.

(UK, Australia, dated) A large pot, often used for heating water or washing clothes over a fire. In Australasia at least, it could also be a fixed installation made of copper, with a fire underneath and its own chimney. Generally made redundant by the advent of the washing machine.

(entomology) Any of various lycaenid butterflies with copper-coloured upperwings, especially those of the genera Lycaena and Paralucia.

(Australia) (informal) synonym of police