Interfacing

Interfacing is a textile used on the unseen or "wrong" side of fabrics to make an area of a garment more rigid.

Some interfacings are loosely-woven muslin-type fabrics, often stiffened with a layer of chemical additive or starch.

A woven interfacing can match the grain of the fashion fabric, enabling it to retain a similar handle and drape.

They are affixed to a garment piece using heat and moderate pressure, from a hand iron for example.

[2] Non-fusible interfacings do not have adhesive and must be sewn by hand or machine.