Source : Free On-Line Dictionary of Computing

Address Strobe
     
         (AS) One of the input signals of a memory device,
        especially {semiconductor} memory, which is asserted to tell
        the memory device that the {address} inputs are valid.  Upon
        receiving this signal the selected memory device starts the
        memory access (read/write) indicated by its other inputs.
     
        It may be driven directly by the {processor} or by a {memory
        controller}.
     
        (1996-10-02)