What is "onomacritus"

Onomacritus (; c. 530 – c. 480 BCE), also known as Onomacritos or Onomakritos, was a Greek chresmologue, or compiler of oracles, who lived at the court of the tyrant Pisistratus in Athens. He is said to have prepared an edition of the Homeric poems, and was an industrious collector, as well as a forger of old oracles and poems.