monotheism [Gr.,=belief in one God], in religion, a belief in one personal god. In practice, monotheistic religion tends to stress the existence of one personal god that unifies the universe. The term is applied particularly to Judaism, Christianity, and Islam, as well as Zoroastrianism. Some eastern religions, notably Vaishava, Saiva, Sikhism, and some Hindu sects, tend to promote the omnipotence of one particular god within the pantheon, and thus display some monotheistic characteristics. Monotheism arose in opposition to polytheism, the belief in many gods. Monism, or nondualism between the physical and the spiritual, presupposes unity but deemphasizes personal monotheism. See also God.