facultative

Từ điển WordNet v3.1 - WordNet Dictionary

adjective

1. of or relating to the mental faculties
• Pertains to noun:
faculty
2. able to exist under more than one set of conditions
- a facultative parasite can exist as a parasite or a saprophyte
• Ant:
obligate
• Topics:
biology, biological science
3. granting a privilege or permission or power to do or not do something
- a facultative enactment
• Similar to:
enabling
4. not compulsory
- facultative courses in the sciences
• Similar to:
optional