Metatron does not appear in the canonical Bible. His name, his identity and his extraordinary status are developed in the Jewish mystical literature of the Talmud, the Midrash and especially the Merkavah (Chariot Mysticism) and Hekhalot (Heavenly Palaces) texts of late antiquity — the tradition of Jewish mysticism that preceded and informed Kabbalah. In 3 Enoch (also known as Sefer Hekhalot, "Book of Heavenly Palaces"), Metatron is the central figure — identified explicitly as the transformed Enoch and described in extraordinary detail.
The etymology of his name is genuinely uncertain — one of the great unsolved puzzles of Jewish angelology. Proposed derivations include the Greek meta thronon ("near the throne" or "behind the throne"), the Latin metator ("one who marks out boundaries" or "a military officer who prepares camp"), and various Hebrew constructions. The uncertainty of the etymology is itself revealing: Metatron is a being whose name resists easy classification, whose origin is genuinely mysterious.
What is consistent across all sources is his supreme rank among the angels. In 3 Enoch he is called "the Prince of the Divine Presence," "the Youth" (Na'ar — referring to his relative newness as an angel compared to the primordial beings), and most controversially "the lesser YHWH" — a designation so startling that it caused significant theological anxiety in the tradition. If Metatron shares God's name, what does this mean for monotheism? The rabbis debated it intensely and one passage in the Talmud (Hagigah 15a) describes a mystic who, upon seeing Metatron seated (an honor normally reserved for God), concluded that there were "two powers in heaven" — a heresy for which Metatron was punished with sixty lashes of fire.