Cartesian Product

In set theory a Cartesian product is a mathematical operation that returns a set (or product set or simply product) from multiple sets. That is, for sets A and B, the Cartesian product A × B is the set of all ordered pairs (a, b) where a ∈ A and b ∈ B.

Cartesian product AxB of two sets A={x,y,z} and B={1,2,3}

References

Wikipedia