Why are police called 'coppers'?

Coppers: some believe it to be an acronym for Constable On Patrol. It is also believed that the term Copper was the original, unshortened word, popularly believed to represent the copper badges American officers used to wear at the time of origin, but in fact probably used in Britain to mean "someone who cops (captures or snatches)" long before this.

Police officers are often referred to as cops, but the word origins of cop are something of a debate. It is known that up until the 1970s, cop was something of a slang term, and one would refer to cops more properly as policemen, or police officers. Some argue that the term cop is shortened from "copper" and derives from the tin or copper badges worn by a policeman. Others say cop is an abbreviation for constabulary of police.

This is an easy one, and being former NYPD I know it for a fact. Police Shields are, and always have been since the term was first coined, made of copper with a silver overlay. This is still true today. I know because at one time my Shield was damaged and before I had it repaired the copper showed through. (It was very annoying.)

Some argue that the term cop is shortened from "copper" and derives from the tin or copper badges worn by a policeman. Others say cop is an abbreviation for constabulary of police.

Because of the copper badges that they used to wear.

http://realpolice.net/police-history.shtml

(under Spoils Era)

I thought it was from the badge: Copper in mad max, they call the police Bronze

I believe it is because, in the old days, the badges were made from copper metal.

you use to be able to "buy them off" for pennies (pennies are made of copper) back in the 40's. Hence the name, "coppers"

Coppers... Cops...

I always thought C.O.P. is an acronym for "Citizen on Patrol", and Coppers is just slang.

back in the day they used to have copper buttons on their uniforms.