Kathenotheism is a term coined by the philologist Max Müller to mean the worship of one god at a time. It is closely related to henotheism. Müller coined the term in reference to the Vedas; where he explained each deity is treated as supreme in turn.
The term kathenotheism, a more specific form of the parent term henotheism, refers to the worship of a succession of supreme gods "one at a time", from the Greek kath' hena "one by one" + theism.
Ancient Greece 
The ancient Orphic religion has a theology comparable to kathenotheism. The Orphic Hymns address each God of the Olympian pantheon as supreme in turn.
The Smarta sect worship the five major deities as supreme in turn and collectively.