The interaction of two or more agents or forces so that their combined effect is greater than the sum of their individual effects.
We want you to do two people's jobs.
"Let's explore the synergies between the marketing and engineering teams." (Translation: marketing needs engineers to build the thing they already promised to a client.)
From the Greek synergos, meaning "working together." Has been aggressively misused since approximately 1995 to justify every merger, reorganization, and open-plan office redesign.