Dry stone means not using mortar to hold the wall together.  Instead, placement of the stone, friction and the skill level of the craftsman work together to hold the wall together.  Advantages of dry stonework include:

• Dry stone walls withstand the freeze/thaw cycle better than mortared walls because they have flexibility
• Dry stone walls allow water to pass through them, eliminating the need to install drain pipes
• Dry stone work draws the eye to the stone itself, instead of the lines between the stone in mortared work
• Repair of dry stone work is easier because you can reuse the stone and do not need to purchase mortar

 Splitting stone with feathers and wedges