SYMBIOSIS

n. arrangement in which two dissimilar organisms live together in what is usually a mutually beneficial manner (Biology);cooperative relationship

The term symbiosis (from the Greek: συμ, sym, "with"; and βίοσίς, biosis, "living") can be used to describe various degrees of close relationship between organisms of different species. The term was first used in 1879 by the German mycologist, Heinrich Anton de Bary, who defined it as: "the living together of unlike organisms".
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Symbiosis /sym·bi·o·sis/ pl. symbio´ses [Gr.] 1. in parasitology, the close association of two dissimilar organisms, classified as mutualism, [more]Symbiosis - Community and Resources

Noun
1. the relation between two different species of organisms that are interdependent; each gains benefits from the other
(synonym) mutualism
(hypernym) mutuality, interdependence, interdependency
(hyponym) trophobiosis

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