sym•bi•o•sis
(s m b - s s, -b -)
n. pl. sym•bi•o•ses (-s z)
1
Biology. A close, prolonged association
between two or more different organisms of
different species that may, but does not
necessarily, benefit each member.
2
A relationship of mutual benefit or
dependence.
[Greek sumbi sis,
companionship, from sumbioun, to live together, from
sumbios, living together : sun-, syn- + bios, life; see
gwei- in Indo-European Roots.]