Definitions of facultative:

  • adjective:   granting a privilege or permission or power to do or not do something
    Example: "A facultative enactment"
  • adjective:   able to exist under more than one set of conditions
    Example: "A facultative parasite can exist as a parasite or a saprophyte"
  • adjective:   of or relating to the mental faculties
  • adjective:   not compulsory
    Example: "Facultative courses in the sciences"