Cooperative play (often abbreviated to co-op) is a gameplay feature that allows two or more human players to work together to defeat computer controlled opponents. This mode of play has existed since the early history of video games, but has only recently risen to notable popularity. This is partially due to the appearance of online co-op where players can work together without having to be in the same room.
While cooperative play may be considered the opposite of competitive play, the two modes are not mutually exclusive (i.e. players may work together to defeat an AI but compete for the highest score). Team competitive play could also be considered a hybrid, especially in a game like Fat Princess
where the opposing team may be fully or partially AI.