Done in cooperation with others: a cooperative effort. Marked by willingness to cooperate; compliant: a cooperative patient. Of, relating to, or formed as an enterprise or organization jointly owned or managed by those who use its facilities or services: a cooperative department store; cooperative apartment buildings. An enterprise or organization that is owned or managed jointly by those who use its facilities or services. A building or complex in which the residents buy shares of stock in a building corporation and are given a lease to a specific apartment. An apartment in such a building or complex.