quaternion

n. 四个一组, 四个一套, 四元数

qua.ter.ni.on

n.（名词）
A set of four persons or items.
四个一组：四个人或项目为一组
Mathematics An expression that is the sum of a real number and a vector and that contains four terms, one real and three imaginary.
【数学】 四元数：一实数和一矢量的和的表达式，有四个项，一个为实数项，另外三个为虚数项

来源：
Middle English quaternioun
中古英语 quaternioun
from Late Latin quaterniô quaterniôn-
源自 后期拉丁语 quaterniô quaterniôn-
from Latin quaterno [by fours]
源自 拉丁语 quaterno [分成四部分]
from quater [four times] * see k wetwer-
源自 quater [四倍] *参见 k wetwer-