trimeter

Trimeter is a metrical line of poetry that contains three feet. The term derives from Latin tri- "three" and metrum "measure," and it is used to describe lines whose length is governed by three rhythmic units rather than one or two. The exact effect of trimeter depends on the type of foot used in each line—most commonly iambs, trochees, or anapests.

Iambic trimeter consists of three iambic feet (an unstressed syllable followed by a stressed one), typically yielding six syllables. Trochaic trimeter uses three trochees (stressed–unstressed), also about six syllables. Anapestic trimeter employs three anapests (two unstressed syllables followed by a stressed one), usually producing nine syllables. The choice of foot shapes the rhythm and emphasis of the line.

Historically, iambic trimeter was the standard line for spoken verse in ancient Greek drama, providing a natural, rapid cadence. In English verse, trimeter appears in ballad stanzas and other lyric forms, often in patterns that pair lines of trimeter with longer lines (for example, ballad stanzas that alternate tetrameter and trimeter lines). Poets may also use trimeter for variety within longer poems or in experimental, contemporary verse.

This article uses trimeter to refer to lines with three metrical feet, regardless of the specific foot chosen. See also meter, iambic, trochaic, anapestic.