symbiosis (n.)

1876, as a biological term, "union for life of two different organisms based on mutually benefit," from Greek symbiosis "a living together," from symbioun "live together," from symbios "(one) living together (with another), partner, companion, husband or wife," from assimilated form of syn- "together" (see syn-) + bios "life" (from PIE root *gwei- "to live"). Given a wider (non-biological) sense by 1921. An earlier sense of "communal or social life" is found in 1620s. A back-formed verb symbiose is recorded from 1960.