1. The interaction of two or more agents or forces so that their combined effect is greater than the sum of their individual effects.
2. Cooperative interaction among groups, especially among the acquired subsidiaries or merged parts of a corporation, that creates an enhanced combined effect.

[From Greek sunergiā, cooperation, from sunergos, working together. See synergism.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.