Base 2, also known as the binary numeral system, is a positional notation system with a radix of 2. In this system, each digit's position represents a power of 2. It uses only two digits, 0 and 1, to represent all possible numerical values. Each digit in a binary number is called a bit (binary digit).
Binary is fundamental in computing because it represents information using electrical or optical signals, where 0 typically illustrates a low voltage or no signal, and 1 represents a high voltage or a signal. It's the foundation of digital electronics and computer programming, where binary digits are manipulated to perform calculations, store data, and execute instructions.