In the United States, the sheriff is the leader of the police department of a county. The USA has 50 states, and each state is divided into counties. Every state has a different number of counties. Most states have about 50 counties but some have 200 counties or more. Anyway, every county has a police department which is run by a sheriff. In many counties the sheriff is actually an elected position so he or she is chosen by voters. A sheriff is not the same as a normal police officer. There is also a difference between a sheriff and a city's Chief of Police. The chief of police is in charge of a city's police, not the county's, and he or she is chosen by the mayor of the city, not elected. County and city police departments are separate and independent groups, although they often cooperate on investigations.

The sheriff is the person Bob Marley shot in his song... remember? of course, in self-defense! http://www.youtube.com/watch?v=2XiYUYcpsT4 Ok, seriously... I have always thought that a sheriff was the person responsable for a group of police officers in a community. I hardly hear that word but when I do, that's what comes to my mind. :)

A sheriff is a town police officer. I think there are still sheriff's in in the western US, but, generally we call just call them officers.

A type of police man. You can see them as characters in Western movies, if you want a fun way to take in some English.