bailiff

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A court attendant entrusted with duties such as the maintenance of order in a courtroom during a trial.
• noun An official who assists a British sheriff and who has the power to execute writs, processes, and arrests.
• noun Chiefly British An overseer of an estate; a steward.

from The Century Dictionary.

• noun A subordinate civil officer or functionary.
• noun An overseer or under-steward on an estate, appointed to manage forests, direct husbandry operations, collect rents, etc. Also called a bailiff of forests, or bailiff in husbandry.
• noun An officer of the Knights of St. John of Jerusalem.
• noun In London, an officer who supervises the inspection of fish brought into the city.

from the GNU version of the Collaborative International Dictionary of English.

• noun Originally, a person put in charge of something; especially, a chief officer, magistrate, or keeper, as of a county, town, hundred, or castle; one to whom powers of custody or care are intrusted.
• noun (Eng. Law) A sheriff's deputy, appointed to make arrests, collect fines, summon juries, etc.
• noun engraving An overseer or under steward of an estate, who directs husbandry operations, collects rents, etc.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun law A legal officer to whom some degree of authority, care or jurisdiction is committed.
• noun UK The steward or overseer of an estate.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun an officer of the court who is employed to execute writs and processes and make arrests etc.