expansion card

noun, Computers.
1.
a card in a computer on which additional chips can be mounted to expand the computer's capabilities.
Also called expansion board.
expansion card in Technology

hardware
A circuit board which can be plugged into one of a computer's expansion slots to provide some optional extra facility such as additional RAM, disk controller, coprocessor, graphics accelerator, communication device or some special-purpose interface.
Different computers have different standards for the cards they accept, e.g. PCI.
(1998-06-26)