Definitions for "Discrete Device"
A device that is not built into the motherboard, but plugs into a slot on the board.  Generally more expensive then integrated devices, but simple to upgrade or replace.
A device that contains one active element, such as a transistor or diode, although a hybrid might contain more than one active element. In comparison, an integrated circuit could contain millions of active elements on a single chip.
An individual electrical or electronic component that must be used in combination with other components to form a complete functional circuit.