Source : Free On-Line Dictionary of Computing

Zero Insertion Force
     
         (ZIF) A kind of socket for {integrated circuit}s.
        A ZIF socket can be opened and closed by means of a lever or
        screw.  When open, there the chip may be placed in the socket
        without any pressure at all, the socket is then closed,
        causing its contacts to grip the pins of the chip.  Such
        sockets are used where chips must be inserted and removed
        frequently, such as in test equipment.  They are more
        expensive and usually take up more space than conventional IC
        sockets.
     
        (1994-12-05)