Each gains benefits from the other

• The relation between two different species of organisms that are interdependent

Wikipedia Word definitions in Wikipedia
Mutualism (also known as the mutualist movement or movement of mutuals ) is a social movement that aims at creating and promoting mutual organizations , mutual insurances , and mutual funds . The movement encourages and assists the provision of mutual benefits ...

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Mutualism \Mu"tu*al*ism\, n. (Ethics) The doctrine of mutual dependence as the condition of individual and social welfare. --F. Harrison. --H. Spencer. --Mallock.

WordNet Word definitions in WordNet
n. the relation between two different species of organisms that are interdependent; each gains benefits from the other [syn: symbiosis ]

Wiktionary Word definitions in Wiktionary
n. (context ecology English) any interaction between two species that benefits both; typically involves the exchange of substances or services

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
1849, in reference to the doctrine of French anarchist/socialist Pierre-Joseph Proudhon (1809-1865), from French mutuellisme . In biology, from 1876, from mutual + -ism .