Do you know the difference between a pillow case and a pillow sham? There are a lot of common misconceptions out there about the difference. Both are technically a pillow cases in that a pillow tucks into each. The real difference between a sham and a case is in their purpose.
A pillow sham is usually more ornate than a pillow case. A sham is usually a lot more decorative and may have embroidery, frills, lace, or some sort of edging. Also, pillow shams are not typically meant to be slept on. Rather, it is solely for decoration.
On the other hand, a pillow case is usually less decorative and more functional. A pillow case is meant for actually sleeping on.