A cylindrical cushion accustomed fill the room that could've already been taken by another person. 1. an extended, often cylindrical, pillow or pillow for a sleep, settee, etc. 2. any such thing resembling this in kind or in use as a support. 3. any pillow, cushion, or pad. 4. Nautical. a. Also called bolster plate. a circular casting privately of a vessel, through which an anchor chain passes. b. a timber made use of as a short-term assistance. c. a beam for keeping outlines or rigging without chafing. d. a bag filled with buoyant material, fitted into a small motorboat. 5. Metalworking. an anvillike help the lower die of a drop forge. 6. Masonry. a. a timber or the like linking two ribs of a centering. b. a chisel with a blade splayed toward the edge, utilized for cutting bricks. 7. Carpentry. a horizontal wood on a post for lessening the no-cost span of a beam. 8. a structural user by which one end of a bridge truss rests. –verb (used with item) 9. to support with or much like a pillow or support. 10. to increase, assistance, or uphold (sometimes fol. by up): They bolstered their morale by singing. He bolstered up their claim with brand new evidence.