[ myoo-choo-uh-liz-uhm ]

  1. a relationship between two species of organisms in which both benefit from the association.

  2. the doctrine that the interdependence of social elements is the primary determinant of individual and social relations, especially the theory that common ownership of property, or collective effort and control governed by sentiments of brotherhood and mutual aid, will be beneficial to both the individual and society.

  1. Sociology. the force or principle of mutual aid.

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Origin of mutualism

First recorded in 1860–65; mutual + -ism

Other words from mutualism

  • mu·tu·al·ist, noun
  • mu·tu·al·is·tic, adjective

Words Nearby mutualism Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use mutualism in a sentence

British Dictionary definitions for mutualism


/ (ˈmjuːtʃʊəˌlɪzəm) /

  1. another name for symbiosis

Derived forms of mutualism

  • mutualist, noun, adjective
  • mutualistic, adjective

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 mutualism


[ myōōchōō-ə-lĭz′əm ]

  1. A relationship between two organisms in which each of the organisms benefits.♦ In obligate mutualism the interacting species are interdependent and cannot survive without each other. The fungi and algae that combine to form lichen are obligate mutualists.♦ In the more common facultative mutualism the interacting species derive benefit without being fully dependent. Many plants produce fruits that are eaten by birds, and the birds later excrete the seeds of these fruits far from the parent plant. While both species benefit, the birds have other food available to them, and the plants can disperse their seeds when the uneaten fruit drops. Compare amensalism commensalism parasitism.

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