Hu is mentioned already in the Old Kingdom Pyramid texts (PT 251, PT 697) as companion of the deceased pharaoh. Together with Sia, he was depicted in the retinue of Thot, with whom he was also occasionally identified.
In the Middle Kingdom, all gods participated in Hu and Sia, and were associated with Ptah who created the universe by uttering the word of creation. Hu was depicted in human shape, as a falcon, or as a man with a ram's head.
As the word of creation, he is comparable to the Hindu concept of Vāc, and the Greek concept of Logos. His name is thought to originate as an onomatopoeia of the act of drawing breath (compare the Hindu and Buddhist notion of AUM). It was later said that Atum split this aspect from himself by extracting blood from his own penis and turning it into Hu (logos) and Saa (sophia).