Stack Segment Register (SS): is used for addressing stack segment of the memory. The stack segment is that segment of memory which is used to store stack data.

While addressing any location in the memory bank, the physical address is calculated from two parts:

• The first is segment address, the segment registers contain 16-bit segment base addresses, related to different segment.
  
• The second part is the offset value in that segment.

The advantage of this scheme is that in place of maintaining a 20-bit register for a physical address, the processor just maintains two 16-bit registers which is within the memory capacity of the machine.