Having relation to the grant or exercise faculty, or authority, privilege, license, or the like hence, optional;
as, facultative enactments, or those which convey a faculty, or permission; the facultative referendum of Switzerland is one that is optional with the people and is necessary only when demanded by petition; facultative studies; -- opposed to
obligatory and
compulsory, and sometimes used with
to. [
Webster 1913 Suppl.]