Final answer:
Groups of lines with the same repeated metrical pattern in a poem are called stanzas, and they are characterized by their consistent meter, such as iambic pentameter or trochaic tetrameter. The quatrain is the most common stanza form.
Step-by-step explanation:
Groups of lines having the same metrical pattern repeated throughout a poem are known as stanzas. The metrical pattern within these stanzas is created by the arrangement of stressed and unstressed syllables, known as meter.
Common metrical patterns include iambic pentameter, which consists of five iambic feet per line, and trochaic tetrameter, which has four trochaic feet per line. The rhythm, or the pattern of stressed and unstressed syllables, gives the poem its musical quality and can significantly affect its overall mood and tone.
The most common stanzaic form is the quatrain, which consists of four lines, often with various rhyme schemes such as AABB or ABAB. Each line within these stanzas adheres to a consistent metrical pattern, although occasionally poets may vary the rhythm to avoid monotony or to emphasize certain words or phrases.
Samuel Taylor Coleridge's "The Rime of the Ancient Mariner" offers an example of quatrain stanzas with alternating eight and six syllable lines.