Facultative

Definition
adjective
(1) Not compulsory; not restricting.
(2) Of, or relating to, mental faculty.
(biology) Capable of existing to more than one set of (environmental) conditions or by assuming various behaviors.
Supplement
For example, facultative bacteria can thrive in both aerobic and anaerobic environments.
Word origin: NL facultātīvus.

Related forms: facultatively (adjective).
Compare: obligate (biology).
Related terms:

• facultative hyperopia
• facultative parasite
• facultative ponds
• facultative species
• facultative mutualism
• facultative anaerobe