What is a couplet in poem?

In poetry, a couplet is a pair of lines that rhyme—typically at the end, although sometimes also internally within the lines in what is formally known as internal rhyme. Couplets were particularly prominent in 18th-century English heroic verse of poets such as Alexander Pope and Samuel Johnson.

Here are more formal definitions of poetic couplets, including some of what may vary with their use:

A pair of successive lines forming a distinct thought

Two lines forming a minor grammatical construction, united by rhyme or cadence, and printed and referred to individually

Any of various verse forms consisting of a repeated couplet of long and short or stressed and unstressed lines forming stanzas

A pair of musical strains with similar rhythm

Here are a few famous examples of rhyming couplets from various ages of English heroic verse and other works:

William Shakespeare, Romeo and Juliet:

But, soft! what light through yonder window breaks?

It is the east, and Juliet is the sun.

Alexander Pope, An Essay on Man, Epistle I:

Hope springs eternal in the human breast;

Man never is, but always to be, blest.

William Butler Yeats, Easter, 1916:

I have met them at close of day

Coming with vivid faces

From counter or desk among grey

Eighteenth-century houses.

William Carlos Williams, Paterson:

By the road to the contagious hospital

under the surge of the blue

mottled clouds driven from the

northeast—a cold wind.