borough

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

• noun A self-governing incorporated town in some US states, such as New Jersey.
• noun One of the five administrative units of New York City.
• noun A civil division of the state of Alaska that is the equivalent of a county in most other US states.
• noun A town having a municipal corporation and certain rights, such as self-government.
• noun A town that sends a representative to Parliament.
• noun A medieval group of fortified houses that formed a town having special privileges and rights.

from The Century Dictionary.

• noun Formerly, a fortified town, or a town possessing municipal organization; also, a town or city in general.
• noun In England: A corporate town possessing a regularly organized municipal government and special privileges conferred by royal charter: usually called a municipal borough.
• noun A town having the right to send one or more representatives to Parliament: usually called a parliamentary borough.
• noun In Connecticut, Minnesota, New Jersey, and Pennsylvania, an incorporated municipality less populous than a city and differently governed: in general, corresponding to town in other States.
• noun A shelter or place of security.
• noun At Richmond in Yorkshire, England, and perhaps other northern old corporate towns, a property held by burgage, and formerly qualifying for a vote for members of Parliament.
• noun An obsolete form of burrow.
• noun An obsolete form of borrow.

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

• noun An association of men who gave pledges or sureties to the king for the good behavior of each other.
• noun The pledge or surety thus given.
• noun In England, an incorporated town that is not a city; also, a town that sends members to parliament; in Scotland, a body corporate, consisting of the inhabitants of a certain district, erected by the sovereign, with a certain jurisdiction; in America, an incorporated town or village, as in Pennsylvania and Connecticut.
• noun The collective body of citizens or inhabitants of a borough.
• noun a borough having the right of sending a member to Parliament, whose nomination is in the hands of a single person.
• noun a name given to any borough which, at the time of the passage of the Reform Bill of 1832, contained but few voters, yet retained the privilege of sending a member to Parliament.

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

• noun obsolete A fortified town
• noun rare A town or city.
• noun A town having a municipal corporation and certain traditional rights.
• noun An administrative district in some cities, e.g., London.
• noun An administrative unit of a city which, under most circumstances according to state or national law, would be considered a larger or more powerful entity; most commonly used in American English to define the five counties that make up New York City.
• noun Other similar administrative units in cities and states in various parts of the world.
• noun A district in Alaska having powers similar to a county.
• noun historical, UK, law An association of men who gave pledges or sureties to the king for the good behaviour of each other.
• noun historical, UK, law The pledge or surety thus given.

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

• noun an English town that forms the constituency of a member of parliament
• noun one of the administrative divisions of a large city