[1] : The Collaborative International Dictionary of English v.0.48

supervisor \su`pervis"or\, n.
   1. one who supervises; an overseer; an inspector; a
      superintendent; as, a supervisor of schools.
      1913 webster

   2. a spectator; a looker-on. obs. --shak.
      1913 webster

[2] : WordNet (r) 2.0

supervisor
     n 1: one who supervises or has charge and direction of
     2: a program that controls the execution of other programs
        syn: supervisory program, executive program
see also:
supervisory program executive program 

[3] : Moby Thesaurus II by Grady Ward, 1.0

70 moby thesaurus words for "supervisor":
   big brother, administrator, alderman, archon, auditor, bailie,
   boatswain, boss, burghermaster, burgomaster, cabinet member,
   cabinet minister, chancellor, chief, city councilman, city father,
   city manager, commissar, commissioner, comptroller, controller,
   councillor, councilman, councilwoman, county commissioner,
   county supervisor, director, elder, floor manager, floorman,
   floorwalker, foreman, gaffer, ganger, governor, head, headman,
   induna, inspector, legislator, lord mayor, magistrate, maire,
   manager, mayor, minister, minister of state, monitor,
   noncommissioned officer, overman, overseer, portreeve, proctor,
   reeve, secretary, secretary of state, selectman, sirdar,
   slave driver, straw boss, subforeman, super, superintendent,
   superior, surveyor, syndic, taskmaster, undersecretary, visitor,
   warden

[4] : Bouvier's Law Dictionary, Revised 6th Ed (1856)

supervisor. an overseer; a surveyor. 
     2. there are officers who bear this name whose duty it is to take care 
of the highways. 

Supervisor >> S Words
Supervisor, definition of term: Supervisor
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