An output stream is a way for a computer program to send data out to a destination, such as a file or a display screen. It allows the program to communicate information, like text or images, to users or other systems. Common examples of output streams include the console output in programming languages like Java and Python, where data is printed for users to see. Output streams can be categorized into different types, such as byte streams and character streams. Byte streams handle raw binary data, while character streams are designed for text data. This distinction helps programmers choose the right method for their specific data output needs.