symbiosis

A relationship of mutual benefit, especially among different species.

(ecology) A close, prolonged association between two or more organisms of different species that normally benefits both members. An interspecies cooperation.

(biology) A close, prolonged association between two or more organisms of different species, regardless of benefit to the members.

The state of people of different types, races, cultures, communities, etc., living together.

The occurrence of two different or opposing things in the same time and place.