God is the concept of a supreme being that created and rules over the universe. In many religions, God is understood as all-powerful, all-knowing, and eternal: the ultimate source of everything that exists. Some religions teach that God created the world, cares about humanity, and sets moral standards for how people should live. Some religions, like Buddhism, are structured less around the concept of God and more around enlightenment, personal behavior, or other ideas.

The word god (lowercase) can also refer to any deity or divine being. Ancient Greeks worshiped gods like Zeus and Athena, while ancient Egyptians prayed to gods like Ra and Osiris. When someone says “thank God,” they're expressing relief or gratitude, though some people use this phrase even if they don't practice a particular religion.

Throughout history, beliefs about God have inspired art, music, literature, and architecture, from Michelangelo's Sistine Chapel to Bach's sacred music to the world's great cathedrals and temples.