Source : Free On-Line Dictionary of Computing

Staggered Pin Grid Array
     
         (SPGA) A style of {integrated circuit} socket or
        pin-out with a staggered grid of pins around the edge of the
        socket, positioned as several squares, one inside the other.
     
        SPGA is commonly used on {motherboards} for {processors},
        e.g. {Socket 5}, {Socket 7} and {Socket 8}.
     
        See also {PGA}.
     
        [Better description?]
     
        (1999-08-04)