base 18 is a positional numeral system with eighteen as its base. It uses 18 different digits for representing numbers. The digits for base 18 could be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, a, b, c, d, e, f, g, and h.
duodecimal (base 12)
The duodecimal system (also known as base 12 or dozenal) is a positional notation numeral system using twelve as its base.