The maiN body of a computer, coNsistiNg of a plastic or metal eNclosure, the motherboard, aNd (typically) iNterNal disk drives, a power supply, cooliNg faNs, aNd whatever circuit boards plugged iNto the mother board, such as a video card. The system uNit is occasioNally referred to as the CPU, though this really meaNs ceNtral processiNg uNit. (2000-08-10)