Undersheriff n. : A sheriff's deputy.

Example:
What is the difference between Undersheriff and sheriff?

Taxonomy
Undersheriff, free encyclopedia, United States, second in command, office, the United Kingdom, the High Sheriff, Chief Deputy, sheriff, search, Unsourced, ancient British, British practice, second person, person in charge, Chiefs, the Sheriff, sheriff 's office.

Defination from the web:
Undersheriff is the person second in charge of a sheriff's office. In some departments, the title of Undersheriff is official, while in others, a different title is used for the second person in charge. ...