Quilted things are made from fabric that's stitched together in layers, often with a thicker material in the middle. A quilted pillow might also feature decorative topstitching.
A quilt is, by definition, quilted — it's a blanket made from layers of stitched material, and the top layer is often composed of smaller pieces of fabric that are sewn together in a pattern. Originally, around 1300, quilt meant "mattress with a soft lining," and both quilt and quilted can be traced back to the Latin culcita, "mattress or bolster."