An Ealdorman, or Alderman, was the prior magistrate of a British shire in A. D. 900 to A. D. 1100. Ealdormanship was the highest form of nobility, up until after A. D. 1100, when ranks such as Barons were introduced. The Ealdormen were the commanders of the armies in the surrounding district (the shire). The Old English word for Ealdormen is Ældormenn, meaning, "older men".

An Ealdormancy was an Anglo-Saxon governing body over several shires, made up of more than one Ealdorman.