Coverlet
A coverlet is a bedcovering with sides that hang down a few inches past the box spring, but don’t touch the floor. A coverlet can be tucked in or left untucked if edged with decorative trim. Luxury coverlets can be layered directly over a flat sheet or over a blanket. It may sometimes resemble a quilt, but unlike a quilt, which is comprised of several layers, a coverlet is just one layer of fabric woven in such a way that mimics the quilting technique. 

The quality of bed sheets is often conveyed by the thread count—the number of threads per square inch of material. In general, the higher the thread count, the softer the sheet, but the weave and type of thread may affect the hand of the material so that a sheet with a lower thread count may actually be softer than one with a higher count. Yarn quality also plays a part in the look and feel of sheets, as finer yarns tend to create a finer sheet fabric. The ply also plays a role in how heavy the sheet feels. Ply represents how many fibers are twisted together as the sheet is being created. A 2 ply 300 thread count sheet will feel heavier than a single ply 600 thread count sheet.