As a symbol, the sun has many meanings. It represents the supreme cosmic power, the all-seeing divinity. It is the heart of the cosmos, the center of being and of intuitive knowledge; the intelligence of the world; enlightenment; glory, splendor; royalty; God the Father, ruler and sustainer of the Universe. It can be a symbol of spiritual illumination, joy and happiness.
In the Tarot Decks, the sun is the XVIIII -th (they always put XVIIII instead of XIX) card of the Major Arcana.