点积（德语：Punktprodukt、英语：Dot Product）是两个矢量上的函数并返回一个标量的二元运算，它的结果是欧几里得空间的标准内积。两个矢量的点积写作a·b，也称作内积(德语：inneres Produkt、英语：Inner Product)、数量积及标量积(德语：Skalarprodukt、英语：Scalar Product))。

矢量的另一种乘法是外积 (德语：Kreuzprodukt 或 Vektorprodukt、英语：Cross Product 或 Vector Product)，写作a×b。

In mathematics, the dot product or scalar product (sometimes inner product in the context of Euclidean space, or rarely projection product for emphasizing the geometric significance), is an algebraic operation that takes two equal-length sequences of numbers (usually coordinate vectors) and returns a single number. This operation can be defined either algebraically or geometrically. Algebraically, it is the sum of the products of the corresponding entries of the two sequences of numbers. Geometrically, it is the product of the Euclidean magnitudes of the two vectors and the cosine of the angle between them. The name "dot product" is derived from the centered dot " · " that is often used to designate this operation; the alternative name "scalar product" emphasizes that the result is a scalar (rather than a vector).