The term 'SMALL NAIL' can be broken down into two crossword solutions: BRAD (4 letters) and TACK (4 letters). A BRAD is a type of nail with a small head and a thin shaft. It is typically used for light-duty fastening, such as attaching paper to a wall or securing two pieces of wood together. A TACK is also a type of nail, but it has a larger head and a thicker shaft than a BRAD. It is usually used for heavier-duty fastening, such as attaching carpeting to a floor.