(1) An expansion card that is used to extend a slot for a chip or card in a fully loaded computer to make room to plug it in. It may also refer to a card that contains several slots used in low-profile, space-saving cabinets. The cards are plugged into the riser card and reside parallel with the motherboard.
(2) A PC expansion card that contains audio, modem and networking capabilities. See also AMR and CNR.