From an uncertain derivation; onar means a dream, specifically a divinely significant dream. Appears six times in Matthew's Gospel alone, always in contexts of divine guidance (the Magi, Joseph's escape to Egypt, return from Egypt, Pilate's wife). It is distinguished from enypnion (ordinary dream) by its divine origin and prophetic character.
Matthew's Gospel is saturated with onar — divine dream-guidance — in a way that deliberately echoes the story of Joseph the dreamer in Genesis. As Joseph (son of Jacob) navigated impossible circumstances through God-given dreams, so Joseph (son of Jacob's descendant) navigates the birth, escape, and return of Jesus through five angelic appearances in dreams. The onar pattern in Matthew 1-2 establishes that the birth of Jesus is under divine guidance at every step — nothing happens by accident. Pilate's wife's onar in Matthew 27:19 ('I have suffered a great deal today in a dream because of him') introduces an unexpected Gentile witness to Jesus' innocence, echoing the dreams of Pharaoh's officials in Genesis 40-41. The NT does not suggest believers should seek direction from dreams regularly; rather, the onar passages show that God is sovereign even over human sleep and can communicate with whoever He chooses in whatever manner He chooses (Acts 2:17 — 'your young men will see visions, your old men will dream dreams').