In mathematics The quaternions form a number system that extends the complex numbers. Quaternion rotation Quaternion group, a non-abelian group of order 8 Symbols Imperial quaternions (heraldry of the Holy Roman Empire) Quaternion Eagle Military uses A group of four soldiers in the Roman legion A fireteam Other Quaternion (gathering), four folded sheets as a unit in bookbinding Quaternion (poetry), a style of poetry with four parts See also