sher·iff 
(shĕrĭf)
(shĕrĭf)n.
1. A public officer in the United States with responsibility for certain law enforcement and administrative legal duties, such as making arrests and serving processes, usually for a particular county.
2. A public officer in various other countries performing certain law enforcement, judicial, or ceremonial functions.
[Middle English, the representative of royal authority in a shire, from Old English scīrgerēfa : scīr, shire + gerēfa, reeve.]