engl. Schnittstelle. Verbindungsgerät zwischen zwei ansonsten unkompatiblen Anschlüssen.
A connection between two "worlds" like USB and Audio, MIDI and USB. Mostly you need interfaces to connect your computer to anything outside like sound generation, synthesizers etc. most of them have MIDI, newer ones got USB also, older ones only got analogue CV + Gate connection as interface which need a MIDI to CV interface to be converted.