Rhyming stanzas made up of two lines. A pair of lines of a verse that form a unit. Some couplets rhyme aa, but this is not a requirement.
COUPLET, a pair of lines of verse, which are welded together by an identity of rhyme. The New English Dict. derives the use of the word from the French couplet, signifying two pieces of iron riveted or hinged together. In rhymed verse two lines which complete a meaning in themselves are particularly known as a couplet. Thus, in Pope’s Eloisa to Abelard:—
“Speed the soft intercourse from soul to soul,
And waft a sigh from Indus to the Pole.”
In much of old English dramatic literature, when the mass of the composition is in blank verse or even in prose, particular emphasis is given by closing the scene in a couplet. Thus, in the last act of Beaumont and Fletcher’s Thierry and Theodoret the action culminates in an unexpected rhyme:—
“And now lead on; they that shall read this story
Shall find that virtue lives in good, not glory.”
In French literature, the term couplet is not confined to a pair of lines, but is commonly used for a stanza. A “square” couplet, in French, for instance, is a strophe of eight lines, each composed of eight syllables. In this sense it is employed to distinguish the more emphatic parts of a species of verse which is essentially gay, graceful and frivolous, such as the songs in a vaudeville or a comic opera. In the 18th century, Le Sage, Piron and even Voltaire did not hesitate to engage their talents on the production of couplets, which were often witty, if they had no other merit, and were well fitted to catch the popular ear. This signification of the word couplet is not unknown in England, but it is not customary; it is probably used in a stricter and a more technical sense to describe a pair of rhymed lines, whether serious or merry. The normal type, as it may almost be called, of English versification is the metre of ten-syllabled rhymed lines designated as heroic couplet. This form of iambic verse, with five beats to each line, is believed to have been invented by Chaucer, who employs it first in the Prologue The Legend of Good Women the composition of which is attributed to the year 1385. That poem opens with the couplet:—
“A thousand times have I heard man tell
That there is joy in heaven and pain in hell.”
This is an absolutely correct example of the heroic couplet, which ultimately reached such majesty in the hands of Dryden and such brilliancy in those of Pope. It has been considered proper for didactic, descriptive and satirical poetry, although in the course of the 19th century blank verse largely took its place. Epigram often selects the couplet as the vehicle of its sharpened arrows, as in Sir John Harington’s
“Treason doth never prosper: what’s the reason?
Why, if it prosper, none dare call it treason.”
A couplet is a type of poem that contains pairs of lines that are of the same length and have the same rhythmic structure, which is known in poetry as meter. The rhyming words in a couplet are typically placed as the last word of each line.
It is not mandatory for the pair of lines to have rhyme scheme at all, as it is common for them to be used as a space filler between lines that do rhyme. The lines can be written in succession of one another or have a line or two placed in between them that does not have the same rhyme structure. A couplet can be written in a formal tone which signals there is a pause at the end of each line indicating the end of a phrase, or as a run on which uses the two lines to finish one continuous thought.
Example (J. Kilmer - Trees):
I THINK that I shall never see (a)
A poem lovely as a tree. (a)
A tree whose hungry mouth is prest (b)
Against the sweet earth's flowing breast; (b)