What is a radix?
Radix is a term used to describe the number of digits utilized in a positional number system before "rolling over" to the next digit's place.
For example, in the base 10 number system, there is a total of 10 digits used (zero through nine), therefore, its radix is 10.
In the base 2 number system, there are two numbers used (zero and one), so its radix is two.
Other words that are synonymous with radix are base and root, in an arithmetic sense.