Source : Webster's Revised Unabridged Dictionary (1913)

Selectman \Se*lect"man\, n.; pl. {Selectmen}.
   One of a board of town officers chosen annually in the New
   England States to transact the general public business of the
   town, and have a kind of executive authority. The number is
   usually from three to seven in each town.

         The system of delegated town action was then, perhaps,
         the same which was defined in an ``order made in 1635
         by the inhabitants of Charlestown at a full meeting for
         the government of the town, by selectmen;'' the name
         presently extended throughout New England to municipal
         governors.                               --Palfrey.

Source : WordNet®

selectman
     n : an elected member of a board of officials who run New
         England towns