Interaction of two substances or organisations (7)

I believe the answer is:

synergy

(Other definitions for synergy that I've seen before include "Extra benefit of working together" , "Mutual cooperation producing greater effect" , "Productive cooperation" , "Coordinated action" , "Combined action" .)

I've seen this clue in The Sun.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.