The Cross Product calculates the cross product of the two input vectors, and outputs another vector.
The Cross Product is a way of multiplying two vectors together. We can calculate the Cross Product of two vectors this way, let's say that the cross product of A and B is vector C:
Cx = Ay × Bx - Az × By
Cy = Az × Bx - Ax × Bz
Cz = Ax × By - Ay × Bx
It outputs the vector that is perpendicular to both input vectors (or the plane spanned by those two vectors).
The length of that vector is equal to the area of the parallelogram formed by those two input vectors (each vector gives a pair of parallel sides). Not that common for this knowledge to be used, you would often use the vector for it's direction and not it's length.