What is a theodicy?

A theodicy is an argument for the existence of God despite their being evil in the world. It attempts to prove the existence of God by arguing that God allows for evil to happen. There are numerous theodicies which differ and have successes and weaknesses, attacked by philosophers such as Mackie. These theodicies include John Hick's vale of soul-making; the free will defence; Augustinian theodicy; Irenaean theodicy.
Most importantly, something is a theodicy if it acknowledges the existence of evil in this world.