synergy (n.)
1650s, "cooperation," from Modern Latin synergia, from Greek synergia "joint work, a working together, cooperation; assistance, help," from synergos "working together," related to synergein "work together, help another in work," from syn- "together" (see syn-) + ergon "work" (see organ). Meaning "combined activities of a group" is from 1847; sense of "advanced effectiveness as a result of cooperation" is from 1957.