mutualism Syllabification: (mu·tu·al·ism)Pronunciation: /ˈmyo͞oCHo͞oəˌlizəm/Definition of mutualism noun the doctrine that mutual dependence is necessary to social well-being. Biology symbiosis that is beneficial to both organisms involved. Derivatives mutualist noun & adjective mutualisticPronunciation: /ˌmyo͞oCHo͞oəˈlistik/ adjective mutualisticallyPronunciation: /ˌmyo͞oCHo͞oəˈlistik(ə)lē/ adverb mutualism in other Oxford dictionaries Definition of mutualism in the British & World English dictionary