Iambic pentameter (/aɪˌæmbɪk pɛnˈtæmɪtər/ eye-AM-bik pen-TAM-it-ər) is a type of metric line used in traditional English poetry and verse drama. The term describes the rhythm, or meter, established by the words in each line. Meter is measured in small groups of syllables called feet. "Iambic" indicates that the type of foot used is the iamb, which in English consists of an unstressed syllable followed by a stressed syllable (as in a-BOVE). "Pentameter" indicates that each line has five metrical feet.
Iambic pentameter is the most common meter in English poetry. It was first introduced into English by Chaucer in the 14th century on the basis of French and Italian models. It is used in several major English poetic forms, including blank verse, the heroic couplet, and some of the traditionally rhymed stanza forms. William Shakespeare famously used iambic pentameter in his plays and sonnets, as did John Milton in his Paradise Lost and William Wordsworth in The Prelude.