n. A covering for the head, worn by men and boys, and differing from a hat chiefly in having no brim; a cap, usually of some soft material.n. A form of hat or head-covering worn by women out of doors.n. The cap, usually of velvet, within the metallic part of a crown, covering the head when the crown is worn.n. In fortification, a small work with two faces, having only a parapet with two rows of palisades about 10 or 12 feet apart.n. Nautical, an addition to a sail, or an additional part laced to the foot of a sail.n. A cast-iron plate covering the openings in the valve-chambers of a pump.n. A frame of wire netting over the chimney of a locomotive engine to prevent the escape of sparks: used chiefly in engines which burn wood.n. In mining, a shield or cover over the cage to protect the miners in case anything should fall down the shaft.n. A cowl or wind-cap for a chimney; a hood for ventilation.n. The hood over the platform of a railroad-car.n. A sliding lid or cover for a hole in an iron pipe.n. A protuberance occurring chiefly on the snout of one of the right whales. It appears to be primitively smooth, but becomes honeycombed by the barnacles which attach themselves to it.n. A decoy; a player at a gaming-table, or bidder at an auction, whose business it is to lure others to play or buy: so called because such a person figuratively bonnets or blinds the eyes of the victims.n. A local name in Florida of the yellow water-lily, Nuphar advena.To force the bonnet or hat over the eyes of, with the view of mobbing or hustling.To pull off the bonnet; make obeisance.n. A portion of a coal-seam left for a roof.n. A flat piece of wood on the top of a prop.n. plural Gas-coal or shale overlying a coal-seam or worked with it.n. The lid or cover of a hole by which access may be had to valves or other apparatus in a closed chamber.n. The protecting hood over the machinery or motor of a motor-vehicle, in front of the dashboard.n. The plate on the motor-crank case, or on the transmission gear, normally closed, through which the cranks and gears of a motor-car can be inspected and cleaned and oiled.n. plural The spatter-dock, Nymphæa advena and the other species. See Nymphæa, 1.To provide with an iron shield or bonnet: as, to bonnet a safety-lamp.