在数学特别是双线性代数中，有同样维度的两个矢量 和 的并矢积

是这些矢量的张量积，而结果是阶为 2 的张量。

关于选定的基 ，并矢积 的分量 可以定义为

,

这里的

,

,

而

.

In mathematics, specifically multilinear algebra, a dyadic or dyadic tensor is a second order tensor, written in a notation that fits in with vector algebra.

There are numerous ways to multiply two Euclidean vectors. The dot product takes in two vectors and returns a scalar, while the cross product returns a pseudovector. Both of these have various significant geometric interpretations and are widely used in mathematics, physics, and engineering. The dyadic product takes in two vectors and returns a second order tensor called a dyadic in this context. A dyadic can be used to contain physical or geometric information, although in general there is no direct way of geometrically interpreting it.