A heroic couplet is a traditional form for English poetry, commonly used for epic and narrative poetry; it refers to poems constructed from a sequence of rhyming pairs of iambic pentameter lines. The rhyme is always masculine:
a rhyme that matches only one syllable, usually at the end of respective lines. Often the final syllable is stressed.
Use of the heroic couplet was first pioneered by Geoffrey Chaucer in the "Legend of Good Women" and the "Canterbury Tales."
A frequently-cited example illustrating the use of heroic couplets is this passage from Cooper's Hill by John Denham:
exercept from Cooper's Hill by John Denham
O could I flow like thee, and make thy stream
My great example, as it is my theme!
Though deep yet clear, though gentle yet not dull;
Strong without rage, without o'erflowing full.