Sewing Glossary–I is for interfacing
Inseam: This term is important when measuring for the length of pants or slacks. The inseam runs from the crotch to the hem.
Interfacing: Interfacing is used to provide shape and body to cuffs, collars, facings, pockets, and sometimes to waistbands. Two types of commercial interfacing are available: fusible and sewn-in. Fusible interfacing is suitable for fabrics which can stand high heat, but it is not appropriate for the most delicate fabrics. Sewn-in interfacing is best for delicate fabrics; some tailored items also work better with sewn-in interfacing.
Invisible zipper: Special zipper which is virtually invisible when closed if applied properly. Invisible zippers are good for wedding gowns, evening gowns, and other special garments. An invisible zipper foot is used to insert invisible zippers.
Iron: A good iron is an important tool for the home sewer. Purchase one which you are comfortable handling. Many different models of irons in all price ranges are now available. Consider their features carefully before you buy.
Ironing: The term ironing means smoothing the fabric by running the iron back and forth over it. Ironing should not be confused with pressing. Pressing means pressing the iron down on the fabric to open up seams set the shape of part of the garment, and so on. When sewing, you will usually press the pieces under construction, rather than iron them.