According to one meaning of the word, an epode is the third part of an ancient Greek choral ode that follows the strophe and the antistrophe and completes the movement.
The word epode is also used to refer to the second, shorter line of a two-line stanza of the kind composed by Archilochus and Hipponax in which the first line consists of a dactylic hexameter or an iambic trimeter. (See Archilochian.) It can also be used (as in Horace's Epodes) to refer to poems written in such stanzas.
Evolution
In the performance of a choral ode, at a certain point in time the choirs, which had previously chanted to the right of the altar or stage, and then to the left of it, combined and sang in unison, or permitted the coryphaeus to sing for them all, while standing in the centre.
The epode soon took its place in choral poetry, which it lost when that branch of literature declined. But it extended beyond the ode, and in the early dramatists we find numerous examples of monologues and dialogues framed on the epodical system. In Latin poetry the epode was cultivated, in conscious archaism, both as a part of the ode and as an independent branch of poetry. Of the former class, the epithalamia of Catullus, founded on an imitation of Pindar, present us with examples of strophe, antistrophe and epode; and it has been observed that the celebrated ode 1.12 of Horace, beginning , possesses this triple character.