Quaternion (n.) : The number four.
Quaternion (n.) : A set of four parts, things, or person; four things taken collectively; a group of four words, phrases, circumstances, facts, or the like.
Quaternion (n.) : A word of four syllables; a quadrisyllable.
Quaternion (n.) : 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.
Quaternion (v. t.) : To divide into quaternions, files, or companies.