What is the etymolgy of the word Zagreus?

In Greek mythology, Zagreus was identified with the god Dionysus and was worshipped by followers of Orphism.

According to the followers of Orphism, Zeus had lain with either Demeter or Persephone in the form of a snake. The result of their union was Zagreus. Zeus had intended Zagreus to be his heir, but a jealous Hera persuaded the Titans to kill the child.

The Titans distracted Zagreus with toys, then carried him away and tore Zagreus to pieces. When the Titans were finished, nothing was left but Zagreus' heart, which Athena rescued and gave to Zeus. From the still-beating heart, Zeus made the body of the mortal Semele. The child was eventually born again, despite Hera's intervention. Some accounts say that he was reassembled and resurrected by Demeter; others, that Zeus fed his heart to Semele in a drink, making her pregnant with Dionysus.

Zeus then obliterated the Titans to ashes with his thunderbolt, and from the ashes came mankind. The ashes explained the mix of good and evil in humans, for humans possessed both a trace of divinity as well as the Titans' maliciousness. ^{[citation needed]}

The Orphics believed in the transmigration of souls and that a person was able to remove their intrinsic evilness by living three virtuous lives. Afterwards, they would dwell in Elysium forever.