Source : WordNet®

interface
     n 1: (chemistry) a surface forming a common boundary between two
          things (two objects or liquids or chemical phases)
     2: (computer science) a program that controls a display for the
        user (usually on a computer monitor) and that allows the
        user to interact with the system [syn: {user interface}]
     3: the overlap where two theories or phenomena affect each
        other or have links with each other; "the interface
        between chemistry and biology"
     4: (computer science) computer circuit consisting of the
        hardware and associated circuitry that links one device
        with another (especially a computer and a hard disk drive
        or other peripherals) [syn: {port}]

Source : Free On-Line Dictionary of Computing

interface
     
         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)