epode

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A lyric poem characterized by distichs formed by a long line followed by a shorter one.
• noun The third division of the triad of a Pindaric ode, having a different or contrasting form from that of the strophe and antistrophe.
• noun The part of a choral ode in classical Greek drama following the strophe and antistrophe and sung while the chorus is standing still.

from The Century Dictionary.

• noun In ancient prosody: A third and metrically different system subjoined to two systems (the strophe and antistrophe) which are metrically identical or corresponsive, and forming with them one pericope or group of systems.
• noun A shorter colon, subjoined to a longer colon, and constituting one period with it; especially, such a colon, as a separate line or verse, forming either the second line of a distich or the final line of a system or stanza. As the closing verse of a system, sometimes called ephymnium.
• noun A poem consisting of such distichs.
• noun Specifically In music, a refrain or burden.

from the GNU version of the Collaborative International Dictionary of English.

• noun The after song; the part of a lyric ode which follows the strophe and antistrophe, -- the ancient ode being divided into strophe, antistrophe, and epode.
• noun A species of lyric poem, invented by Archilochus, in which a longer verse is followed by a shorter one. It does not include the elegiac distich.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun poetry The after song; the part of a lyric ode which follows the strophe and antistrophe.
• noun poetry A kind of lyric poem, invented by Archilochus, in which a longer verse is followed by a shorter one.