Elective

Part of speech: noun (n.)

In an American college, an optional study or course of study. [Colloq.]

Part of speech: adjective (a.)

1. Exerting the power of choice; selecting; as, an elective act.

2. Pertaining to, or consisting in, choice, or right of choosing; electoral. The independent use of their elective franchise. Bancroft.

3. Dependent on choice; bestowed or passing by election; as, an elective study; an elective office. Kings of Rome were at first elective; . . . for such are the conditions of an elective kingdom. Dryden. Elective affinity or attraction (Chem.), a tendency to unite with certain things; chemism.