| Noun | 1. | CPU board - the main circuit board for a computerC.P.U., central processing unit, central processor, CPU, mainframe, processor - (computer science) the part of a computer (a microprocessor chip) that does most of the data processing; "the CPU and the memory form the central part of a computer to which the peripherals are attached" add-in, circuit board, circuit card, plug-in, board, card - a printed circuit that can be inserted into expansion slots in a computer to increase the computer's capabilities |