Evan Morris's Sunday Daily News column explained "Cop." I like the

little poem in this explanation, from the Philadelphia Inquirer, Everybody's

Column, 19 February 1905, pg. 8, col. 7:

A "COP" (C. B. L.).--"Please tell me in Everybody's Column how the word

"cop" came to be applied to the policemen.

There has been a favorite rhyme among English schoolboys for generations

past which says:

"He that cops what isn't his'n,

Will be copped and put to prison."

This verb "to cop," you see, is an old-timer, meaning "to take," "to

catch," "to capture;" naturally enough a "copper" is a "catcher" (a

policeman); and (although none of our dictionaries says so) "cop" seems to us

to be nothing more than a free-and-easy popular abbreviation of "copper."