noun

• 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.