This term for 2 dissimilar organisms living together in mutualism comes from the Greek for "with" & "life"
... 1: the living together of two dissimilar organisms in more or less 
intimate... [DOC] [TLE] Symbiosis - definition of symbiosis by The Free Dictionary [PAR] [C19: via New Latin from Greek: a living together; see symbiont] ... a. the living 
together of two dissimilar organisms, as in mutualism, commensalism,... [DOC] [TLE] Symbiotic relationship - definition of Symbiotic relationship by The ... [PAR] ... sumbioun, to live together, from sumbios, living together : sun-, syn- + bios, life; 
see gei- ... a. the living together of two dissimilar organisms, as in mutualism, ... [
161525; < Greek symbsis=symbi-, variant s. of symbion to live together (
sym- .... who achieved a symbiotic relationship with the city; Armstrong, a native 
son... [DOC] [TLE] Symbiosis - Interactive Biology, with Leslie Samuel [PAR] Some believe symbiosis should only refer to persistent mutualisms, while ...