In Kabbalah, Adam Kadmon also called Adam Elyon, or Adam Ila'ah, sometimes abbreviated as A"K, is the first of Four Worlds that came into being after the contraction of God's infinite light. Adam Kadmon is not the same as the physical Adam Ha-Rishon.
Adam Ḳadmon—Diagram illustrating the Sefirot (Divine Attributes). (From Christian Ginsburg, The Kabbalah - its Doctrines, Development & Literature)
The Four Worlds, sometimes counted with a prior stage to make Five Worlds, are the comprehensive categories of spiritual realms in Kabbalah in the descending chain of Existence.
Jacob's vision in Genesis 28:12 of a ladder between Heaven and Earth. In Kabbalistic interpretation, the Sulam-ladder's four main divisions are the Four Worlds and the angelic hierarchy embody external dimensions of the lights-vessels, while souls embody inner dimensions
Ezekiel's Tomb in Iraq. Ezekiel's vision of the Divine Merkabah-Chariot, and Isaiah's vision of the Kisei HaKavod-Throne of Glory, are related in Kabbalah to beholding the Four Worlds from Yetzirah, and from Beriah