Definition of "facultative" in English

adjective

1. Of or relating to faculty, especially to mental faculty.

2. Not obligate; optional, discretionary or elective.

3. That grants permission or power to do something.

4. (biology) Able to perform a particular life function, or to live generally, in more than one way.

   • facultative feeder

5. (geometry, of a point) At which a given function is positive.