quatrain

Quatrain is a stanza or complete poem of four lines. The term derives from the French quatrain, from quatre, meaning "four." Quatrains are among the most common stanzaic forms in world poetry, appearing in many languages and across different historical periods.

In English-language poetry, a quatrain is a versatile building block for longer works and a common unit in ballads and sonnets. While lines are often arranged in meter, many quatrains use iambic rhythm, frequently in tetrameter or pentameter, though variations occur. A quatrain may stand alone or serve as a subdivision within a larger poem, such as the Shakespearean sonnet, which comprises three quatrains followed by a final couplet.

Rhyme schemes for quatrains are varied. The best-known English patterns are AABB, ABAB, ABBA, and ABCB; a quatrain can also be unrhymed or unified by a single rhyme (monorhyme). Some traditions employ strict formal schemes, while others permit freer rhyme within the four lines.

Quatrains have a long cross-cultural presence. In Persian and Arabic poetry, the four-line rubai (rubaiyat) is a major form; the Rubáiyát of Omar Khayyám popularized it in translation. In Western poetry, quatrains recur in medieval and Renaissance verse, in ballads and in sonnets, and remain common in modern lyric poetry.