In poetry, two successive lines that rhyme and share the same meter form a couplet.
A couplet is a compact poetic unit, often used to complete an idea, deliver a punchline, or provide a memorable conclusion. A formal or closed couplet has an end-stopped first line and second line, so each line forms a grammatical unit. In a run-on or open couplet, the sentence continues across the line break, creating a different rhythm and emphasis.
Couplets are especially prominent in English heroic verse. The heroic couplet typically uses rhyming pairs of iambic-pentameter lines, with five metrical feet per line. Geoffrey Chaucer helped establish the form in English, and Alexander Pope later made it famous for satire, argument, and polished epigrams. Shakespeare also frequently used rhyming couplets to close scenes or speeches.
Not every pair of adjacent poetic lines is technically a rhyming couplet: modern poets may arrange unrhymed couplets using spacing or visual design. A tercet has three lines, while a quatrain has four. A refrain is a repeated line or phrase, so it describes a recurring element rather than a two-line stanza.