This paper deals with the significance of the enigmatic hieroglyph of a young bird within an egg, and its variations. It presents related matters of its significance; hieroglyphic structure in comparison with similar hieroglyphs; its metaphorical connections with similar hieroglyphs and the signs in its combinations as well as its symbolism to the cosmogony of the egg and its mythical role. One of the main aims of this paper is to reveal the assimilation of this hieroglyph with the iconography of the child sun god inside his disk in the First hour of Book of the Day, and Book of the Deads, etc. This assimilation is approved and interpreted here through the various related texts, and ideas of the sun god who emerges from his egg and the metaphorical resemblance of the sun disk to the egg.