A boundary across which two systems communicATe. An interface might be a hardware connector used to link to other devices, or it might be a convention used to allow communicATion between two software systems. Often there is some intermediATe component between the two systems which connects their interfaces together. For example, two EIA-232 interfaces connected via a serial cable. See also graphical user interface, {ApplicATion Program Interface}. (1996-05-22)