A motherboard is the main circuit board in a computer that connects all the components like the CPU, memory, storage drives, and ports. It acts as the central hub and allows the components to communicate. Over time, motherboards have evolved from connecting components with wires to using printed circuit boards. Key developments in motherboards include the introduction of the microprocessor in the 1970s and major manufacturers like Intel planning to produce their own motherboards in the late 1990s.