» For engineering gussets, see gusset plate. In sewing, a gusset is a triangular or square piece of fabric inserted into a seam to add breadth or reduce stress. Gussets were used at the shoulders, underarms, and hems of traditional shirts and chemises made of rectangular lengths of linen to shape the garments to the body. Gussets are used in manufacturing of modern tights or pantyhose to add breadth at the crotch seam; these gussets are often made of breathable fabrics for hygiene on wearing pa… (More on Gusset)