A heroic couplet is a specific type of couplet commonly used in epic poetry, consisting of two rhyming lines written in iambic pentameter.
Iambic Pentameter: A metrical pattern consisting of five pairs (or feet) of unstressed/stressed syllables per line.
Unrhymed verse written in iambic pentameter.
Epic Poetry: A long narrative poem that tells the story of heroic deeds and adventures.