The capital Latin letter Z is used in mathematics to represent the set of integers. Usually, the letter is presented with a "double-struck" typeface to indicate that it is the set of integers.
The Latin letter z is used to represent a variable or coefficient. The symbol z is also used to represent the up/down dimension in the 3D cartesian coordinate system.
Set of integers symbol.
The set of integers is made up of the set of counting integers and each of their negative counter parts.