There are various names of God, many of which enumerate the various qualities of a Supreme Being. The English word god is used by multiple religions as a noun to refer to different deities, or specifically to the Supreme Being, as denoted in English by the capitalized and uncapitalized terms God and god. Ancient cognate equivalents for the biblical Hebrew Elohim, one of the most common names of God in the Bible, include proto-Semitic El, biblical Aramaic Elah, and Arabic ilah. The personal or proper name for God in many of these languages may either be distinguished from such attributes, or homonymic. For example, in Judaism the tetragrammaton is sometimes related to the ancient Hebrew ehyeh. It is connected to the passage in Exodus 3:14 in which God gives his name as אֶהְיֶה אֲשֶׁר אֶהְיֶה, where the verb, translated most basically as "I am that I am" or "I shall be what I shall be", "I shall be what I am" In the Hebrew Bible, YHWH, the personal name of God, is revealed directly to Moses. Correlation between various theories and interpretation of the name of "the one God", used to signify a monotheistic or ultimate Supreme Being from which all other divine attributes derive, has been a subject of ecumenical discourse between Eastern and Western scholars for over two centuries. In Christian theology the word is considered a personal and a proper name of God. On the other hand, the names of God in a different tradition are sometimes referred to by symbols. The question whether divine names used by different religions are equivalent has been raised and analyzed.

In monotheistic belief systems, God is usually viewed as the supreme being, creator, and principal object of faith. In polytheistic belief systems, a god is "a spirit or being believed to have created, or for controlling some part of the universe or life, for which such a deity is often worshipped". Belief in the existence of at least one god is called theism.