Theism is the belief in (or knowledge of) God as an active, immanent force in the universe. Generally - in as far as the vast majority of theists are monotheists - theism normally implies monotheism. Informally, theism simply means belief in God (as contrasted with atheism, the belief that there is/are no God/s). In this general sense, theism also indicates the belief that God is a person.
In theological circles, however, theism is a doctrine specifying the nature of God's relationship with the universe. Theists believe that God is very much involved in the events and development of the world. In this theological sense theism is contrasted with doctrines such as deism.
Monotheism is the belief that there is only one deity. [2]
Inclusive monotheism: The belief that there is only one deity, and that all other claimed deities are just different names for it. The Hindu denomination of Smartism is an example of inclusive monotheism.
Exclusive monotheism: The belief that there is only one deity, and that all other claimed deities are distinct from it and false — either invented, demonic, or simply incorrect. Most Abrahamic religions, and certain versions of the Hindu denomination of Vaishnavism, such as ISKCON which regard the worship of anyone other than Vishnu as incorrect are examples of exclusive monotheism.
The earliest known form of monotheism still in practice is Judaism.
Polytheism
Polytheism is the belief that there is more than one deity.[3] In practice, polytheism is not just the belief that there are multiple gods; it usually includes belief in the existence of a specific pantheon of distinct deities.
Within polytheism there are hard and soft varieties:
Hard polytheism views the gods as being distinct and separate beings; an example of this would be ancient Greek Mythology.
Soft polytheism views the gods as being subsumed into a greater whole. Most forms of Hinduism serve as examples of soft polytheism.
Polytheism is also divided according to how the individual deities are regarded:
Henotheism: The belief that there may be more than one deity, but one is supreme.
Monolatry: The belief that there may be more than one deity, but only one should be worshiped.
Kathenotheism: The belief that there is more than one deity, but only one deity at a time should be worshiped. Each is supreme in turn.
Divisions by natures of deities
Misotheism: the belief that some god or gods are evil.
Pantheism: The belief that the physical universe is equivalent to God, and that there is no 'division'.[4]
Panentheism: Like Pantheism, the belief that the physical universe is joined to God. However, it also believes that God is greater than the universe.
Cosmotheism: The belief that man is The Creator. Man and the cosmos are one, thus the will of man is the will of the cosmos and the will of the cosmos is the will of man.
Deism is the belief that a god or gods exists, but does not interact with the known universe.[5] It typically rejects supernatural events (prophecy, miracles) and divine revelation prominent in organized religion, along with holy books and revealed religions that assert the existence of such things. Instead, Deism holds that religious beliefs must be founded on human reason and observed features of the natural world, and that these sources reveal the existence of a supreme being as creator.[6]
Pandeism: The belief that God preceded the universe and created it, but is now equivalent with it.
Polydeism: The belief that multiple gods existed, but do not intervene with the universe.