What does alderman mean?
The definition of alderman
Al”der*man, n.; pl. Aldplwmen.
Etym: [AS. aldormon, ealdorman; ealdor an elder + man. See Elder, n.]

1 A senior or superior; a person of rank or dignity. [Obs.]

Note: The title was applied, among the Anglo-Saxons, to princes, dukes, earls, senators, and presiding magistrates; also to archbishops and bishops, implying superior wisdom or authority. Thus Ethelstan, duke of the East-Anglians, was called Alderman of all England; and there were aldermen of cities, counties, and castles, who had jurisdiction within their respective districts.

3 One of a board or body of municipal officers next in order to the mayor and having a legislative function. They may, in some cases, individually exercise some magisterial and administrative functions.