Quaternion is a poetry style in which the theme is divided into four parts.

Each part of a quaternion explores the complementary natures of the theme or subject. The word quaternion is derived from the Latin word quaterni, meaning "four by four".^[1] The poem may be in any poetic form and 'offers poets the chance to experiment with varied rhetorical structures'.^[2]

Anne Bradstreet, America's first significant poet, wrote four quaternions:

• "Four Seasons"
• "Four Elements" (Fire, Earth, Water and Air)
• "Of the Four Humours of Man's Constitution" (sanguine, pragmatic, choleric and melancholic)
• "Of the Four Ages of Man" (Childhood, Youth, Manhood and Old Age)
• "The Four Monarchies" (Assyrian, Persian, Grecian, and Roman)

Elizabeth Daryush, known for her syllabic verse, used the quaternion form in her poem "Accentedal".^[3]

• Quaternion examples