n. One who or that which folds; specifically, a flat knife-like instrument, frequently of bone or ivory, used in folding paper.n. A circular, time-table, map, or other printed paper folded in such a way that it may be spread out in one sheet.n. In entomology, one of many insects which fold leaves: as, the grape-leaf folder. See Desmia and leaf-folder.n. An attachment to a sewing-machine for bending and folding the fabric previous to sewing. It is made in a great variety of forms to produce the different plaits, folds, and bands used in garment-making and in decorative sewing.n. In sheet-metal work, a hand-power machine for folding over the edges of sheet-metal plates to form a lock, turning the edges of small tinware and roofing-plates, etc.: a tin-folding machine.