What Does Mutually Beneficial Mean?

The phrase mutually beneficial is used to mean mutually dependent. Synonyms for the same include the terms interdependent, mutualist.

The phrase is typically used when a given act or relationship will work to the advantage of both or all parties involved. Mutually beneficial relationships are seen in all spheres of life. Right from the business world to the plant kingdom such relationships are vital for basic functioning.  

A related term is the word symbiosis, which in biology means an alliance between two or more dissimilar organisms belonging to different species that is close and prolonged, which may, though not necessarily, benefit those involved. The term could also be broadened to mean a relationship that is of mutual benefit or dependence. It is when both partners benefit, that the type of symbiosis is termed as mutualism.