Headless

A headless computer is a computer system or device that has been configured to operate without a monitor (the missing "head"), keyboard, and mouse. A headless system is typically controlled over a network connection, although some headless system devices require a serial connection to be made over RS-232 for administration of the device.

Headless operation of a server is typically employed to reduce operating costs or to minimize size for convenient deployment - e.g. embedded systems.