peace officer

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A law enforcement officer, such as a sheriff, who is responsible for maintaining civil peace.

Century Dictionary and Cyclopedia

1. n. A civil officer whose duty it is to preserve the public peace, especially to prevent or quell riots and other breaches of the peace, as a sheriff or constable.

GNU Webster's 1913

1. n. a civil officer whose duty it is to preserve the public peace, to prevent riots, etc., as a polliceman, sheriff or constable.

WordNet 3.0

1. n. an officer of the law