A motherboard (sometimes alternatively known as the mainboard, main circuit board, system board, baseboard, planar board or logic board, or colloquially, a mobo) is the main printed circuit board (PCB) found in general purpose computers and other expandable systems. It holds and allows communication between many of the crucial electronic components of a system, such as the central processing unit (CPU) and memory, and provides connectors for other peripherals. Unlike a backplane, a motherboard usually contains significant sub-systems such as the central processor, the chipset’s input/output and memory controllers, interface connectors, and other components integrated for general purpose use and applications.
Motherboard specifically refers to a PCB with expansion capability and as the name suggests, this board is often referred to as the “mother” of all components attached to it, which often include peripherals, interface cards, and daughtercards: sound cards, video cards, network cards, hard drives, or other forms of persistent storage; TV tuner cards, cards providing extra USB or FireWire slots and a variety of other custom components.
Similarly, the term mainboard is applied to devices with a single board and no additional expansions or capability, such as controlling boards in laser printers, televisions, washing machines, mobile phones and other embedded systems with limited expansion abilities.
A circuit board that is an extension of a motherboard or other card.
“daughtercard|mezzanine board|piggyback board”
The primary circuit board of a personal computer, containing the circuitry for the central processing unit, keyboard, mouse and monitor, together with slots for other devices.
a small printed circuit board that attaches to a larger one.
a printed circuit board containing the principal components of a computer or other device, with connectors for other circuit boards to be slotted into.