Cartesian product

The Cartesian product of two sets $A, B$ , denoted by $A \times B$ , is the set of all possible ordered pairs whose first component is an element of $A$ and whose second component is an element of $B$ .

Definition
Given two sets $A, B$ , $A\times B=\Big\{(x,y)|x\in A\and y\in B\Big\}$

Example

Suppose $A=\{0,1\}$ and $B=\{a,c\}$ :

$A\times B=\Big\{(0,a),(0,c),(1,a),(1,c)\Big\}$