quaternion

quaternion is a Noun

Definition:

[1] The number four. [Poetic]

[2] A set of four parts, things, or person; four things taken collectively; a group of four words, phrases, circumstances, facts, or the like. Delivered him to four quaternions of soldiers. Acts xii. 4. Ye elements, the eldest birth Of Nature`s womb, that in quaternion run. Milton. The triads and quaternions with which he loaded his sentences. Sir W. Scott.

[3] A word of four syllables; a quadrisyllable.

[4] The quotient of two vectors, or of two directed right lines in space, considered as depending on four geometrical elements, and as expressible by an algebraic symbol of quadrinomial form.