Monotheism is the belief that one God is the only, or at least the dominant deity. A distinction may be made between exclusive monotheism, in which the one God is a singular existence, and both inclusive and pluriform monotheism, in which multiple gods or godly forms are recognized, but each are postulated as extensions of the same God.
Monotheism is distinguished from henotheism, a religious system in which the believer worships one god without denying that others may worship different gods with equal validity, and monolatrism, the recognition of the existence of many gods but with the consistent worship of only one deity. The term monolatry was perhaps first used by Julius Wellhausen.
Monotheism characterizes the traditions of Abrahamic religions such as Judaism, Samaritanism, Christianity, Islam, and the early derivatives of these faiths, including Druzism.
Other early monotheistic traditions include Atenism of ancient Egypt, Platonic and Neoplatonic belief in the Monad, Mandaeism, Manichaeism, Waaqeffanna, and Zoroastrianism.
Monotheistic traditions from post-antiquity and the early modern period comprise Deism, Yazidism, and Sikhism, with varying degrees of influence from Abrahamic monotheism. Many new religious movements are monotheistic such as Bábism, the Baháʼí Faith, Seicho-no-Ie, and Tenrikyo.
Narrow monotheism and wide monotheism exist on a spectrum of belief. Narrow monotheism holds that only one exclusive deity exists, disallowing others, while wide monotheism acknowledges one supreme deity and permits lesser deities. Elements of wide monotheistic thought are found in early religions such as ancient Chinese religion, Tengrism, and Yahwism.