What is a cooperative?

The cooperative is a type of shop, which sells food and things.

Or, in real estate law, a cooperative is a multi-family dwelling in which ownership is accomplished by buying shares in a closely-held corporation whose sole asset is the building and real estate the building sits on. (if I remember correctly)

There are also farm cooperatives in which a group of farmers cooperate together to decide what should be grown, who will grow it and which land shall be used and they split the profits and food grown. The help one another with all aspects of the farming.
This is an organization being run and managed by a group of pursuing a common mutual goal.