Applique is a basic technique. In concept, one piece of cloth is applied to another, Often to create decorative patterns or designs.  Traditionally this involves turning under the raw edges.

I have included Wikipedia's definition here, just for a bit of background, and also because they used my Flickr picture (with permission) as their feature photo. Ha! But also, I like the reference to the patch. A way to mend. Within that context I see applique as a way to mend design also, covering, filling, decorating space.  And that is why I consider Applique as a type of PATCHWORK.