Fabric is purchased in different measurements for quilting.  One common measurement for quilting purposes is the "Fat Quarter".  A fat quarter of fabric is 1/2 the width of the fabric (usually about 22 inches) by a 1/2 yard of length or 18 inches. A piece of cotton measuring 18" x 22" inches is what is generally referred to by the term Fat Quarter.  Many quilts typically use 20 of these Fat Quarters in their design of the top or front side.  Larger pieces are often used for sashing- the strips between the blocks and borders and binding - the edging along the outside of the overall quilt top.  Some quilters purchase bundles of preselected Fat Quarters for the overall effect of the colors or patterns combined in the set.  Others will purchase individual Fat Quarters for adding to their fabric stash so that later when looking for just the right pattern or color they'll already have it on hand to work with. Fat quarters are a great way for any beginning quilter to accumulate a fabric stash with great variety due to the generally lower costs involved in acquring multiple pieces of fabric.