In number system, base 16 is called "hexadecimal".
We use different number systems in our daily lives to represent and manipulate numbers. The most common number system is the decimal system, which uses ten digits (0, 1, 2, 3, 4, 5, 6, 7, 8, 9) to represent all numbers.
However, in some computer science and engineering applications, it is more convenient to use the hexadecimal number system, which uses 16 digits (0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F) to represent numbers. The letters A through F are used to represent the numbers 10 through 15, respectively.
For example, the decimal number 15 is represented as F in hexadecimal, and the decimal number 255 is represented as FF in hexadecimal.
So, to summarize, base 16 is called "hexadecimal" because it uses 16 digits to represent numbers, and it is commonly used in computer science and engineering applications.