Tritheism

Tritheism is the belief that there are three distinct, powerful gods, who form a triad. Generally three gods are believed to have separate powers and separate supreme beings or spheres of influence but working together. In this respect tritheism differs from dualism, which typically envisages two opposed Divine powers in conflict with one another.
Ironically, there is no group that claims to believe in or teach tritheism; the term is solely used as an accusation against others, somewhat similar to the usage of the word "cult", in accusing a group of holding an alternate or distorted view of the Christian doctrine of Trinity. The main branches consider tritheism heretical.