Standard input is a way for a computer program to receive data from the user or another program. It typically comes from the keyboard, allowing users to type commands or information that the program can then process. This input is essential for interactive applications, where user interaction is necessary for the program to function. In many programming languages, standard input is represented by a specific function or method that reads the data. For example, in Python, the `input()` function is commonly used to capture user input. This allows developers to create dynamic applications that respond to user commands and data in real-time.