Quaternion can refer to:

Mathematics Quaternions, a number system that extends the complex numbers. Quaternion rotation, systems for describing how rotation groups and quaternions interact Quaternion group (Q8), a non-abelian group of order 8 that describes the quaternions

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