Answer:

Monotheism, belief in the existence of one god, or in the oneness of God. As such, it is distinguished from polytheism, the belief in the existence of many gods, from atheism, the belief that there is no god, and from agnosticism, the belief that the existence or nonexistence of a god or of gods is unknown or unknowable. Monotheism characterizes the traditions of Judaism, Christianity, and Islam, and elements of the belief are discernible in numerous other religions.