copper

Concise Oxford English Dictionary © 2008 Oxford University Press:
copper1

▶noun

• 1 a red-brown metal, the chemical element of atomic number 29, which is a good conductor of electricity and heat and is alloyed to form brass and bronze. (Symbol: Cu)

• 2 (coppers) Brit. coins of low value made of copper or bronze.

• 3 Brit. dated a large copper or iron container for boiling laundry.

• 4 a reddish-brown colour.

• 5 a small butterfly with bright reddish-brown wings. [Lycaena phlaeas (small copper) and related species.]

▶verb cover or coat with copper.

– derivatives
coppery adjective.

– origin OE copor, coper, based on late L. cuprum, from L. cyprium aes ‘Cyprus metal’ (so named because Cyprus was the chief source).

Concise Oxford English Dictionary © 2008 Oxford University Press:
copper2

▶noun Brit. informal a police officer.

– origin C19: from cop1 + -er1.