n. Belief in or worship of one deity without denying the existence of other deities.
the GNU version of the Collaborative International Dictionary of English
n. Primitive religion in which each of several divinities is regarded as independent, and is worshiped without reference to the rest.
The Century Dictionary and Cyclopedia
n. A name given to an asserted characteristic of the oldest Hindu religion (of the Vedas), as ascribing supreme power to different gods in turn: hence also sometimes applied to similar phases of other polytheistic religions.
Word Usage
"Recently, while browsing through the dictionary, I came across the word henotheism, defined as "the worship of one of a group of gods, in contrast with monotheism, which teaches that only one god exists.""