[oh-dis-ee-uh
s, oh-dis-yoos] 
| king of Ithaca; son of Laertes; one of the heroes of the Iliad and protagonist of the Odyssey: shrewdest of the Greek leaders in the Trojan War. |
| O·dys·seus (ō-dĭs'yōōs', ō-dĭs'ē-əs) n. Greek Mythology The king of Ithaca, a leader of the Greeks in the Trojan War, who reached home after ten years of wandering. |
A Greek hero in the Trojan War. Odysseus helped bring about the fall of Troy by conceiving the ruse of the Trojan horse. After Troy was ruined, Odysseus wandered for ten years trying to return home, having many adventures along the way. (See Circe, Cyclops, Penelope, Scylla and Charybdis, and Sirens.)
Note: The story of Odysseus' journey home is told in the Odyssey of Homer. By extension, an “odyssey” is any long or difficult journey or transformation.