Bū_bāt: (Arabic: underarm/armpit, synonym: Ibt, bāt, tkhrāṣah, tnfāyah, bnqīyah), gusset, a triangular or rhomboidal piece of fabric inserted into the seam to add breadth or reduce stress from tight-fitting clothing. Used for underarms on tunic dresses, side sleeve panels on overgarments (thāwb), and undergarments (ṣarāwl).