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-
