facultative has definitions from the field of biology
1
[ adjective ] granting a privilege or permission or power to do or not do something

Examples

"a facultative enactment"

Related terms

enabling

2
[ adjective ] (biology) able to exist under more than one set of conditions

Examples

"a facultative parasite can exist as a parasite or a saprophyte"

Related terms

obligate biology

3
[ adjective ] of or relating to the mental faculties

Related terms

faculty

4
[ adjective ] not compulsory

Examples

"facultative courses in the sciences"

Related terms

optional

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