God

God is the supreme, self-existent being who subsists in three Divine Persons: God the Father, God the Son, and God the Holy Spirit. He is both Creator and Sustainer of the universe.

Etymology of the Word "God"
God can variously be defined as: The root-meaning of the name (from Gothic root gheu; Sanskrit hub or emu, "to invoke or to sacrifice to") is either "the one invoked" or "the one sacrificed to." From different Indo-Germanic roots (div, "to shine" or "give light"; thes in thessasthai "to implore") come the Indo-Iraniandeva, Sanskrit dyaus (gen. divas), Latin deus, Greek theos, Irish and Gaelic dia, all of which are generic names; also Greek Zeus (gen. Dios, Latin Jupiter (jovpater), Old Teutonic Tiu or Tiw (surviving in Tuesday), Latin Janus, Diana, and other proper names of pagan deities. The common name most widely used in Semitic occurs as 'el in Hebrew, 'ilu in Babylonian, 'ilah in Arabic, etc.; and though scholars are not agreed on the point, the root-meaning most probably is "the strong or mighty one."
 * the proper name of the one Supreme and Infinite Personal Being, the Creator and Ruler of the universe, to whom man owes obedience and worship;
 * the common or generic name of the several supposed beings to whom, in polytheistic religions, Divine attributes are ascribed and Divine worship rendered;
 * the name sometimes applied to an idolas the image or dwelling-place of a god.

Existence of God
The existence of God is the basic presupposition of logic. The necessity of one supreme, self-existent Being is foundational to existence.

Saint Thomas Aquinas (Summa Theologica I:2:3; Cont. Gent., I, xiii) and after him many scholastic writers advance the five following arguments to provethe existence of God: To these many Theists add other arguments:
 * Motion, i.e. the passing from power to act, as it takes place in the universe implies a first unmoved Mover (primum movens immobile), who is God; else we should postulate an infinite series of movers, which is inconceivable.
 * For the same reason efficient causes, as we see them operating in this world, imply the existence of a First Cause that is uncaused, i.e. that possessesin itself the sufficient reason for its existence; and this is God.
 * The fact that contingent beings exist, i.e. beings whose non-existence is recognized as possible, implies the existence of a necessary being, who is God.
 * The graduated perfections of being actually existing in the universe can be understood only by comparison with an absolute standard that is also actual, i.e., an infinitely perfect Being such as God.
 * The wonderful order or evidence of intelligent design which the universe exhibits implies the existence of a supramundane Designer, who is no other than God Himself.
 * the common consentof mankind (usually described by Catholic writers as the moral argument),
 * from the internal witnessof conscience to the supremacy of the moral law, and, therefore, to the existence of a supreme Lawgiver (this may be called the ethical argument, or
 * from the existenceand perception of beauty in the universe (the aesthetical argument).

Other classical arguments used to confirm the existence of God include the Cosmological, Ontological, and Teleological Arguments.

Attributes of God
According to both the Bible and philosophical reasoning, God has and maintains in perpetuity the following attributes:
 * Self-existence
 * Self-sufficiency
 * Eternality
 * Infinite love
 * Absolute moral perfection
 * Omnipotence
 * Omnipresence
 * Omniscience
 * Transcendence
 * Ultimate sovereignty

Nature of God
God is completely infinite, absolutely simple, and only one, while simultaneously existing as an eternal communion of three Divine Persons: God the Father, God the Son, and God the Holy Spirit.