The sentence that precisely defines an ode is that It's written in homage to a person, idea, or an object.
For instance, John Keats composed Ode to Psyche, in the truthfulness of a person, and Ode on Melancholy, in recognition of an impression, and Ode on a Grecian Urn, in consideration of an object. Odes exist regarding ancient times, so they aren't just ancient poems. Heroic achievements are described in chronicles, not odes. Tragic episodes are recorded in elegies.
