facultative

[ fak-uh l-tey-tiv ]
/ ˈfæk əlˌteɪ tɪv /

adjective

conferring a faculty, privilege, permission, or the power of doing or not doing something: a facultative enactment.
left to one's option or choice; optional: The last questions in the examination were facultative.
that may or may not take place; that may or may not assume a specified character.
Biology. having the capacity to live under more than one specific set of environmental conditions, as a plant that can lead either a parasitic or a nonparasitic life or a bacterium that can live with or without air (opposed to obligate).
of or relating to the faculties.

Origin of facultative

From the New Latin word facultātīvus, dating back to 1810–20. See faculty, -ive

OTHER WORDS FROM facultative

fac·ul·ta·tive·ly, adverb non·fac·ul·ta·tive, adjective

Example sentences from the Web for facultative

British Dictionary definitions for facultative

facultative
/ (ˈfækəltətɪv) /

adjective

empowering but not compelling the doing of an act
philosophy that may or may not occur
insurance denoting a form of reinsurance in which the reinsurer has no obligation to accept a particular risk nor the insurer to reinsure, terms and conditions being negotiated for each reinsurance
biology able to exist under more than one set of environmental conditions a facultative parasite can exist as a parasite or a saprotroph Compare obligate (def. 4)
of or relating to a faculty

Derived forms of facultative

facultatively, adverb

Medical definitions for facultative

facultative
[ făkəl-tā′tĭv ]

adj.

Capable of functioning under varying environmental conditions. Used of certain organisms, such as bacteria that can live with or without oxygen.
Capable of occurring along various pathways or under various conditions.

Scientific definitions for facultative

facultative
[ făkəl-tā′tĭv ]

Capable of existing under varying environmental conditions or by assuming various behaviors. Bacteria that are facultative aerobes can live in both aerobic and anaerobic environments. A facultative parasite can live independently of its usual host. Compare obligate.