A mutually beneficial relationship between two living organisms is called symbiosis.

There are different types of symbiosis, depending on the nature of the relationship:

* Mutualism: Both organisms benefit from the interaction. This is the most common type of symbiosis.

* Commensalism: One organism benefits, while the other is neither harmed nor helped.

* Parasitism: One organism benefits at the expense of the other.

So, while "symbiosis" is the general term, mutualism specifically describes a relationship where both organisms benefit.