God is most often held to be incorporeal (immaterial). Some religions describe God without reference to gender, while others use masculine terminology, using such terms as "Him" or "Father," and some religions (such as Judaism) attribute only a purely grammatical "gender" to God. Incorporeity and corporeity of God are related to conceptions of transcendence (being outside nature) and immanence (being in nature, in the world) of God, with positions of synthesis such as the "immanent transcendence".
God has been conceived as either personal or impersonal. In theism, God is the creator and sustainer of the universe, while in deism, God is the creator, but not the sustainer, of the universe. In pantheism, God is the universe itself. In atheism, God is not believed to exist, while God is deemed unknown or unknowable within the context of agnosticism. God has also been conceived as the source of all moral obligation, and the "greatest conceivable existent". Many notable philosophers have developed arguments for and against the existence of God.
The many different conceptions of God, and competing claims as to God's characteristics, aims, and actions, have led to the development of ideas of omnitheism, pandeism, or a perennial philosophy, which postulates that there is one underlying theological truth, of which all religions express a partial understanding, and as to which "the devout in the various great world religions are in fact worshipping that one God, but through different, overlapping concepts or mental images of Him."
Monotheists refer to their gods using names prescribed by their respective religions, with some of these names referring to certain cultural ideas about their god's identity and attributes. In the ancient Egyptian era of Atenism, possibly the earliest recorded monotheistic religion, this deity was called Aten, premised on being the one "true" Supreme Being and creator of the universe. In the Hebrew Bible and Judaism, "He Who Is", "I Am that I Am", and the tetragrammaton YHWH (Hebrew: יהוה, traditionally interpreted as "I am who I am"; "He Who Exists") are used as names of God, while Yahweh and Jehovah are sometimes used in Christianity as vocalizations of YHWH. In the Christian doctrine of the Trinity, God, consubstantial in three persons, is called the Father, the Son, and the Holy Spirit. In Judaism, it is common to refer to God by the titular names Elohim or Adonai. In Islam, the name Allah is used, while Muslims also have a multitude of titular names for God. In Hinduism, Brahman is often considered a monistic concept of God. In Chinese religion, God (Shangdi) is conceived as the progenitor (first ancestor) of the universe, intrinsic to it and constantly ordaining it. Other religions have names for God, for instance, Baha in the Bahá'í Faith, Waheguru in Sikhism, and Ahura Mazda in Zoroastrianism.
The earliest written form of the Germanic word God (always, in this usage, capitalized) comes from the 6th-century Christian Codex Argenteus. The English word itself is derived from the Proto-Germanic * ǥuđan. The reconstructed Proto-Indo-European form * ǵhu-tó-m was likely based on the root * ǵhau(ə)-, which meant either "to call" or "to invoke". The Germanic words for God were originally neuter—applying to both genders—but during the process of the Christianization of the Germanic peoples from their indigenous Germanic paganism, the words became a masculine syntactic form.