A gusset is a triangular or rhomboidal piece of fabric, plastic, metal, or wood that is inserted into a seam to add breadth or reduce stress from tight-fitting clothing. Gussets were traditionally used at the shoulders, underarms, and hems of shirts and chemises made of tight-fitting fabric. They can also be used when making three-piece bags, for example, in a pattern for a bag as a long, wide piece which connects the front piece and back piece. By becoming the sides and bottom of the bag, the gusset opens the bag up beyond what simply attaching the front to the back would do. Gussets are also used in retort pouches and other forms of packaging to allow the package to stand.
The meaning of gusset has expanded beyond fabric to denote an added patch of joining material that provides structural support. For example, metal gussets are used in bicycle frames to add strength and rigidity. Gussets may also be used in construction projects and home improvement, such as in building bridges and reinforcing joints.
In womens underwear, a gusset refers to the extra layer of fabric sewn into the crotch portion of the underwear. Mens underwear may also have a gusset, but its far more common in womens panties. Gussets can be found in just about every type of underwear for women, from boyshorts to bikini panties to thongs.
