Devices such as the keyboard, mouse, scanner, and even a digital camera are considered input devices. This is because they allow the user to input data into the computer (yes, the word "input" can also be used as a verb). While input generally comes from humans, computers can also receive input from other sources. These include audio and video devices that record movies and sound, media discs that install software, and even the Internet, which is used to download files and receive data such as e-mail or instant messages.
The opposite of input is output, which is what the computer produces based on user input. Input and output devices are collectively referred to as I/O devices.