Source : Free On-Line Dictionary of Computing

linear address space
     
        A memory addressing scheme used in processors where the whole
        memory can be accessed using a single address that fits in a
        single register or instruction.  This contrasts with a
        {segmented memory} architecture, such as that used on the
        {Intel 8086}, where an address is given by an offset from a
        base address held in one of the "segment registers".  Linear
        addressing greatly simplifies programming at the {assembly
        language} level but requires more instruction word bits to be
        allocated for an address.
     
        (1995-02-16)