Okay, here we have this:
Considering the definition requested, we obtain that:
Base: It refers to the number of digits used, or it can be a combination of numbers and letters that are generally used in a counting system to represent numbers.
Examples: The most common system is the decimal that uses the digits from 0 to 9 to represent all the numbers in the counting system. There are also others such as hexadecimal, octal, binary, etc.