Standard Input/Output (often abbreviated as I/O) refers to the methods by which a program receives input from the user and displays output. In many programming languages, standard input is typically the keyboard, while standard output is usually the screen. This allows users to interact with programs easily. In programming, functions like scanf in C or input in Python are used to read data from standard input. Similarly, functions like printf in C or print in Python send data to standard output. This standardization simplifies the way programs handle user interaction.