COP

Hello again, Thank You for your reponse re: GOP.
I'm not trying to be funny but I would also like to ask about "COP" referring to a policeman.
Someone had told me that it meant "Chief Of Police"
at one time. Is this true? Acronyms are used so often
that the original words are sometimes forgotten for years.

I've heard "constable on patrol" all my life, but I'm not near my trusty OED to verify.