Wordnet 3.0
NOUN (2)
1. 
 a long wandering and eventful journey; 
2. 
 a Greek epic poem (attributed to Homer) describing the journey of Odysseus after the fall of Troy; 
The Collaborative International Dictionary of English v.0.48:
Odyssey \Od"ys*sey\ ([o^]d"[i^]s*s[y^]), n. [L. Odyssea, Gr.
   'Ody`sseia, fr. 'Odyssey`s Ulysses: cf. F. Odyss['e]e.]
   An epic poem attributed to Homer, which describes the return
   of Ulysses to Ithaca after the siege of Troy.
   [1913 Webster]
WordNet (r) 3.0 (2006):
odyssey
    n 1: a long wandering and eventful journey
    2: a Greek epic poem (attributed to Homer) describing the
       journey of Odysseus after the fall of Troy