The Djed is a very ancient Egyptian symbol of stability. It resembles a short pillar with four horizontal, stacked platforms on top. It is a symbolic representation of the Tree that entombed the god Osiris at his death by the hand of his brother Seth. The Djed was central in a festival in honor of the god called “the Raising of the Djed.” The Djed also stood in for the phallus of the god, and represented the cosmic axis, or Tree of Life.
The Djed can also be viewed as a symbolic of the human spinal cord.
The Pharoah Seti l Raising the Djed, from Abydos