What does the symbol on back of Edward jacket mean?

The symbol on the back of Edward Elric's jacket from the anime series "Fullmetal Alchemist" is the Ouroboros symbol. The Ouroboros is an ancient symbol depicting a serpent or dragon eating its own tail, forming a circle. It represents the cyclical nature of life, death, and rebirth, as well as the concept of eternity and the unity of opposites.

In the context of "Fullmetal Alchemist," the Ouroboros symbol is associated with alchemy and the concept of human transmutation, which is a forbidden practice that attempts to create or alter living beings through alchemical means. The Ouroboros symbol serves as a reminder to Edward and his brother Alphonse of the consequences of attempting to play God and the cycle of suffering that can result from it.