A multi-core CPU is a computer processor which has two or more sections. Each section of the chip executes instructions as if it was a separate computer. The actual processors are still on one chip. On this chip every core looks mostly like the other. They are several mostly independent cores which work together in parallel. A dual-core processor is a multi-core processor with two independent microprocessors. A quad-core processor is a multi-core processor with four independent microprocessors. As you might be able to tell from the prefix, the name of the processor is based on the number of the microprocessors on the chip.