from The American Heritage® Dictionary of the English Language, 4th Edition
- n. An association between organisms of two different species in which each member benefits.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. any interaction between two species that benefits both; typically involves the exchange of substances or services
from the GNU version of the Collaborative International Dictionary of English
- n. The doctrine of mutual dependence as the condition of individual and social welfare.
from The Century Dictionary and Cyclopedia
- n. A symbiosis in which two organisms living together mutually and permanently help and support one another.
- n. Lichens are examples among plants.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. the relation between two different species of organisms that are interdependent; each gains benefits from the other
mutual + -ism (Wiktionary)