[1] : The Collaborative International Dictionary of English v.0.48

motherboard \moth"erboard`\ n. electronics
   the board containing the main circuits of an electronic
   device, especially computers. the term is used primarily in
   microcomputer literature, where it designates the board
   containing the main expansion bus, and usually also the cpu.
   on motherboards designed with an expansion bus, often all of
   the circuits not contained on an expansion card are on the
   motherboard.
   pjc

[2] : The Free On-line Dictionary of Computing (27 SEP 03)

motherboard
     
         mobo the main printed circuit board in an
        electronic device, particularly a computer, which may contain
        sockets that accept additional boards "daughter-boards".
     
        in a personal computer, the motherboard contains the bus,
        the microprocessor, and integrated circuits used for
        controlling any built-in peripherals such as the keyboard,
        text and graphics display, serial ports and parallel
        ports, joystick, and mouse interfaces.
     
        2000-08-10
     
     
see also:
printed circuit board personal computer bus microprocessor integrated circuits peripherals 
keyboard serial ports parallel ports joystick mouse 
interfaces 

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Motherboard, definition of term: Motherboard
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