An expansion slot is a port on a motherboard that accepts an expansion card. An expansion slot is a socket on a computer motherboard that allows you to add additional components to your system. In computers, a slot, or expansion slot, is an engineered technique for adding capability to a computer in the form of connection pinholes (typically. An expansion slot is a socket on the motherboard that is used to insert an expansion card (or circuit board), which provides additional features. In computing, an expansion card is a printed circuit board that can be inserted into an electrical connector, or expansion slot on a computer's motherboard. Certain industrial PCs are equipped with expansion slots that can house expanded function boards (expansion cards). An expansion slot is used to add an adapter to the motherboard. It has rules that control how many bits can be transferred at a time to the. These slots are used to expand the. Typical slot formats include PCIe and PCI. . The meaning of EXPANSION SLOT is a socket on the motherboard of a computer into which an expansion card may be inserted. In computing, an expansion card is a printed circuit board that can be inserted into an electrical connector, or expansion slot on a computer's motherboard to add functionality to a computer system. This article covers expansion cards in. Alternatively known as a bus slot or expansion port, an expansion slot is a connection or port inside a computer on the motherboard or riser.