Vectors

Vectors need not correspond to a physical quantity; anything can be a vector space as long as vector addition and scalar multiplication is defined.

Most people are introduced to vectors in high school or college.

It's common and there are numerous vectors.

Rats are vectors of disease.

The dot product of two vectors is defined as the sum of the products of the respective components of the two vectors.

The dot product of two vectors can be expressed as a function of their lengths and the angle between them.