An ode is an elaborately structured poem praising or glorifying an event or individual, describing nature intellectually as well as emotionally. A classic ode is structured in three major parts: the strophe, the antistrophe, and the epode. Different forms such as the homostrophic ode and the irregular ode also enter.
wikipedia:ode
The definition of ode given above is very good one. The word originates from the same word in Greek Ωδή (ode).