- Quaternion
- Quaternion Qua*ter"ni*on, n. [L. quaternio, fr. quaterni four
each. See {Quaternary}.]
1. The number four. [Poetic]
[1913 Webster]
2. A set of four parts, things, or person; four things taken collectively; a group of four words, phrases, circumstances, facts, or the like. [1913 Webster]

Delivered him to four quaternions of soldiers. --Acts xii. 4. [1913 Webster]

Ye elements, the eldest birth Of Nature's womb, that in quaternion run. --Milton. [1913 Webster]

The triads and quaternions with which he loaded his sentences. -- Sir W. Scott. [1913 Webster]

3. A word of four syllables; a quadrisyllable. [1913 Webster]

4. (Math.) 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. [1913 Webster]

Note: The science or calculus of quaternions is a new mathematical method, in which the conception of a quaternion is unfolded and symbolically expressed, and is applied to various classes of algebraical, geometrical, and physical questions, so as to discover theorems, and to arrive at the solution of problems. --Sir W. R. Hamilton. [1913 Webster]

*The Collaborative International Dictionary of English.
2000.*