A Simultaneous Exhibition, or Simultaneous Display, is an event on which one person, usually a chess master, is playing multiple chess games at the same time against many opponents. In chess circles this event is commonly referred to as a “Simul”.
World Champion Bobby Fischer, playing a Simul against 50 opponents.
At our club we occasionally organize chess simuls with masters. Young chess players have a great opportunity to play (and score!) against a master, and after the game to receive advise and guidance.