四元數

quaternion (math.)

four / 4

surname Yuan / the Yuan or Mongol dynasty (1279-1368)

currency unit (esp. Chinese yuan) / first / original / primary / fundamental / constituent / part / era (of a reign) / meta- (prefix) / (math.) argument / variable / (Tw) (geology) eon

to count / to count as / to regard as / to enumerate (sb's shortcomings)

number / figure / several / CL:個|个[ge4]

frequently / repeatedly