The term digital derives from the word "digit," as in a counting device.
Digital services represent data in a binary (using 1s and 0s) fashion. Rather than a physical quantity, a digital signal is an informational stream of code that tells a computer to reproduce a perfect replica of the original code stream. This means the digital code can be duplicated nearly infinitely and without any degradation of quality.
A digital system uses discrete values rather than the continuous spectrum values of analog. The word "digital" can refer to the type of data storage and transfer, the internal working of a device, or the type of display.