Theism is broadly defined as the belief in the existence of at least one deity. In common parlance, or when contrasted with deism, the term often describes the classical conception of God that is found in monotheism (also referred to as classical theism) — or gods found in polytheistic religions — a belief in God or in gods without the rejection of revelation as is characteristic of deism. Gnosticism is the belief in personal spiritual knowledge. Atheism is commonly understood as non-acceptance or rejection of theism in the broadest sense of theism, i.e. non-acceptance or rejection of belief in God or gods. Related, but separate, is the claim that the existence of any deity is unknown or unknowable: agnosticism. Combined with theism, is agnostic theism. Etymology The term theism derives from the Greek (theós) or theoi meaning "god" or "gods". The term theism was first used by Ralph Cudworth (1617–1688). In Cudworth's definition, they are "strictly and properly called Theists, who affirm, that a perfectly conscious understanding being, or mind, existing of itself from eternity, was the cause of all other things". Types of theism Monotheism Monotheism (from Greek ) is the belief in theology that only one deity exists. Some modern day monotheistic religions include Judaism, Christianity, Islam, Baháʼí Faith, Sikhism, Zoroastrianism, some Sects of Hinduism, and Eckankar. Polytheism Polytheism is the belief in multiple deities, which are usually assembled into a pantheon, along with their own religious sects and rituals. Polytheism was the typical form of religion before the development and spread of the Abrahamic religions of Judaism, Christianity, and Islam, which enforce monotheism. It is well documented throughout history, from prehistory and the earliest records of ancient Egyptian religion and ancient Mesopotamian religion to the religions prevalent during Classical antiquity, such as ancient Greek religion and ancient Roman religion, and in ethnic religions such as Germanic, Slavic, and Baltic paganism and Native American religions. Notable polytheistic religions practiced today include Taoism, Shenism or Chinese folk religion, Japanese Shinto, Santería, most Traditional African religions, various neopagan faiths such as Wicca. Hinduism, while popularly held as polytheistic, cannot be exclusively categorised as such as some Hindus consider themselves to be pantheists and others consider themselves to be monotheists. Both are compatible with Hindu texts, since there exists no consensus of standardisation in the faith. Vedanta, the most dominant school of Hinduism, offers a combination of monotheism and polytheism, holding