Deity
A deity or a god, is a postulated supernatural entity, usually, but not always, of significant power, worshipped, thought holy, divine, or sacred, held in high regard, or respected by humans. They assume a variety of forms, but are frequently depicted as having human or animal form. Sometimes it is considered blasphemous to imagine the deity as having any concrete form. They are usually immortal. They are commonly assumed to have personalities and to possess consciousness, intellects, desires, and emotions much like humans. Such natural phenomena as lightning, floods, storms, other “acts of God”, and miracles are attributed to them, and they may be thought to be the authorities or controllers of every aspect of human life (such as birth or the afterlife). Some deities are asserted to be the directors of time and fate itself, to be the givers of human law and morality, to be the ultimate judges of human worth and behavior, and to be the designers and creators of the Earth or the universe.
They are generally thought to be invisible or inaccessible to humans — to dwell mainly in otherworldly, remote or secluded and holy places, such as Heaven, Hell, the sky, the under-world, under the sea, in the high mountains, or deep forests, or in a supernatural plane or a celestial sphere — choosing but rarely to reveal or manifest themselves to humans, and to make themselves known mainly through their effects. While the monotheistic God of Judaism, Christianity, and Islam is thought of as dwelling in Heaven, he is also said to be omnipresent, though invisible.
Some human rulers, such as the Roman Emperors, or the Emperor of Japan, have been worshipped by their subjects as deities while still alive, and in many cultures rulers and other prominent or holy persons may be thought to become deities upon death. Deities are sometimes thought to parent children with humans, and the children, demi-gods, often have god-like characteristics and may go to dwell with the gods. In many cultures, the rulers are believed to have descended from gods.
Philology
The English word deity is from the Latin deus or Greek theos, meaning ‘god’. Zeus was the supreme Greek divinity. Similar is the Sanskrit deva, a god or celestial being. Related are words for the sky: Latin dies, day, divum, the open sky, Sanskrit div, diu, sky, day, shine. Also related are divine or divinity from Latin divinus from divus, dius. The English word god is from the Anglo-Saxon, and similar words are found in many Germanic languages.
God
In some cases, especially the God of monotheism, or the supreme deity of henotheistic religions, the divine entity is not thought by some believers in the same terms as deities — as a powerful, human-like, supernatural being — but rather becomes esoteric, the reification of a philosophical category — the Ultimate, the Absolute Infinite, the Transcendent, the One, the All, Existence or Being itself, the ground of being, the monistic substrate, etc.
In this view, God (Allah, Brahman, Waheguru, Elohim, etc…) is not a god or deity, and the anthropomorphic mythology and iconography associated with Him is regarded as symbolism, allowing worshippers to speak and think about something which otherwise would be beyond human comprehension.
Religion
Theories and narratives about, and modes of worship of, gods are largely a matter of religion. At present, the vast majority of humans are adherents of some religion, and this has been true for at least thousands of years. Human burials from between 50,000 and 30,000 B.C. provide evidence of human belief in an afterlife and possibly in gods, although it is not clear when human belief in deities became the dominant view.
Some religions are monotheistic and assert the existence of a unique god. In the English language, the common noun “god” is equivalent to “deity”, while “God” (capitalized) is the name of the unique deity of monotheism. Pantheism considers the Universe itself to be a deity. Dualism is the view that there are two deities: a deity of Good who is opposed and thwarted by a deity of Evil, of equal power. Manichaeism, Zoroastrianism, and Gnostic sects of Christianity are, or were, dualist. Polytheism asserts the existence of several gods, who together form a pantheon. Henotheism is a form of polytheism in which one god is worshipped as supreme. Monolatrism is a type of polytheism in which gods are believed to exert power only on those who worship them. Animism is the belief that spirits inhabit every existing thing, including plants, minerals, animals and, including all the elements, air, water, earth, and fire. The anthropologist E. B. Tylor argued that religion originally took an animist form. Theism is the view that at least one god exists. Atheism is the view that there are no gods or God.
It may not be readily apparent what form a religion actually takes. Religions that avow monotheism may in fact be henotheistic in that they recognize the existence of several echelons of supernatural, immortal, deity-like beings in addition to the supreme God, such as angels, saints, Satan, demons, and devils, although these beings may not be considered deities. Adherents of polytheistic religions, such as certain schools of Hinduism, may regard all gods in the pantheon as manifestations, aspects, or multiple personalities of the single supreme god, and the religions may be more akin to monotheism or henotheism than is initially apparent to an observer.
The many religions do not in general agree on which gods exist, although sometimes the pantheons may overlap, or be similar except for the names of the gods. It is frequently argued that Judaism, Christianity, and Islam all worship the same monotheistic god, although they differ in many important details. Comparative religion studies the similarities and contrasts in the views and practices of various religions. The Philosophy of religion discusses philosophical issues related to theories about gods. Narratives about gods and their deeds are referred to as myths, the study of which is mythology. The word “myth” has an overtone of fiction; so religious people commonly (although not invariably) refrain from using this term in relation to the stories about gods in which they believe themselves.