A. Sutherland – AncientPages.com – In Egyptian beliefs, the soul had three parts, the Ka, the Ba, and the Akh. These three spiritual elements found refuge in the body. Therefore, it was vital to keep the body intact after death and to equip it with the necessary items for life.
The Ba was a spiritual aspect of an individual, usually depicted as a bird with a human head, and in this form, the Ba of a deceased person was able to move through the underworld and then, revisit the earth by day.
Left: The Ba of Queen Nefertari, representing her unique character, stood before a false door, an architectural feature found on the west walls of tombs and mortuary temples. Food would be placed on an offering table in front of the door, serving as a link between the living and the dead. The ka would leave the burial chamber to partake of the offerings, providing sustenance for the deceased. The ba was expected to unite with the ka in order to transform the deceased into akh. Source; Right: One of many ancient depictions of Queen Nefertari. Credit: Public Domain
So, the Ba-bird represented the ancient Egyptian concept of the soul.
The Ba was power and just as the gods had power (which they could multiply at will), so also the people had their Ba.
In the beginning – during the Old Kingdom (c. 2613-2181 BC) – the Ba was only attributed to the god-king, and was expressed with the sign of the ‘jabiru-bird’.