An output stream is a sequence of data that is sent from a program to a destination, such as a file or a display screen. It allows programs to communicate information, like text or binary data, to users or other systems. Common examples of output streams include standard output (stdout) for displaying text in a console and file output streams for writing data to files. In programming, output streams are often used in conjunction with input streams, which handle incoming data. They can be manipulated using various functions and methods, enabling developers to format and control how data is presented. This is essential for creating user-friendly applications and managing data effectively.