ˈfakəlˌtād.iv adjective
Etymology: French facultatif, from faculté faculty + -atif -ative
1.
a. : having relation to or concerned with the grant of a privilege
facultative legislation or enactments
: involving permission rather than compulsion
the licensing provision is purely facultative
b. of money : used for convenience and having no status as legal tender
at one time local subdivisions of France issued facultative coins of small value
c. : optional
facultative courses in the sciences
2.
a. : having characteristics that permit alternate responses (as of doing or not doing or of happening or not happening) under different conditions
there is no facultative plurality in the mind; it is a single organ of true judgment — James Martineau
facultative homosexuals
b. : able to live or thrive under more than one set of conditions
certain facultative parasites that are capable of a free-living saprophytic existence
many bacteria are facultative anaerobes
3. : of or relating to the faculties
4. : nondistinctive