An alderman is a member of a municipal assembly or council in many jurisdictions founded upon English law

English law

English law is the legal system of England and Wales, and is the basis of common law legal systems used in most Commonwealth countries and the United States except Louisiana...

. The term may be titular, denoting a high-ranking member of a borough or county council, a council member chosen by the elected members themselves rather than by popular vote, or a council member elected by voters.

The title is derived from the Old English title of ealdorman

Ealdorman

An ealdorman is the term used for a high-ranking royal official and prior magistrate of an Anglo-Saxon shire or group of shires from about the ninth century to the time of King Cnut...

, literally meaning "elder man", and was used by the chief nobles presiding over shire

Shire

A shire is a traditional term for a division of land, found in the United Kingdom and in Australia. In parts of Australia, a shire is an administrative unit, but it is not synonymous with "county" there, which is a land registration unit. Individually, or as a suffix in Scotland and in the far...

s.
Many local government bodies used the term "alderman" in Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

.