#master  directs the work of other
  supertype:  employer  a person or firm that employs workers
  subtype:  postmaster  the person in charge of a post office
     subtype:  postmistress  a woman postmaster
  subtype:  stationmaster__station_agent__stationagent  the person in charge of a railway station

No statement uses or specializes master; click here to add one.