[kwəˈtəːnɪən], (Noun)

Definitions:
- a complex number of the form w + xi + yj + zk, where w, x, y, z are real numbers and i, j, k are imaginary units that satisfy certain conditions.

- a set of four people or things.


Phrases:

Origin:
Middle English (in sense quaternion (sense 2)): from late Latin quaternio(n-), from Latin quarterni (see quaternary)