Fabric used in sewing to stiffen individual pieces of cloth or entire parts of garments. It can be either woven or created using a felting process.

It comes in two varieties:

• stitchable interfacing, which is sewn in place. It is used to firm up an area of a garment, such as the front of a jacket. (Note that cheaper jackets sometimes use fusible interfacing there, which causes the fabric to pucker after a few dry cleanings.)
• fusible interfacing - basically stitchable interfacing with dots of glue on one side. Ironing it onto fabric melts the glue dots and sticks it on. Commonly used in the waistbands of fitted trousers and skirts.