facultative

[ fak-uhl-tey-tiv ]
See synonyms for facultative on Thesaurus.com
adjective
  1. conferring a faculty, privilege, permission, or the power of doing or not doing something: a facultative enactment.

  2. left to one's option or choice; optional: The last questions in the examination were facultative.

  1. that may or may not take place; that may or may not assume a specified character.

  2. 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).

  3. of or relating to the faculties.

Origin of facultative

1
First recorded in 1820-25; from French facultative (feminine) “conveying or granting a right or power,” from faculté “knowledge, learning, physical or moral capacity,” ultimately from Latin facultāt-, the stem of facultās (originally a doublet of the noun facilitās “ease, ease of performance or completion, facility”) “ability, power, capacity” + -ative adjective suffix; see faculty, -ive

Other words from facultative

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

Words Nearby facultative

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use facultative in a sentence

  • Similarly the saphrophytes are classed as obligatory saphrophytes and facultative parasites.

  • If a parasite cannot exist outside animal tissues, it is an obligatory parasite; if it can, it is a facultative saphrophyte.

  • I have seen this particularly in those cases where facultative divergence also was greater than usual.

    Schweigger on Squint | C. Schweigger
  • Moreover, the extent of the "facultative" divergence attainable by prisms shows a considerable latitude.

    Schweigger on Squint | C. Schweigger
  • (b) Both saprophytic and facultative parasitic bacteria agree in requiring non-concentrated food.

British Dictionary definitions for facultative

facultative

/ (ˈfækəltətɪv) /


adjective
  1. empowering but not compelling the doing of an act

  2. philosophy that may or may not occur

  1. 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

  2. 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)

  3. of or relating to a faculty

Derived forms of facultative

  • facultatively, adverb

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for facultative

facultative

[ făkəl-tā′tĭv ]


  1. 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.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.