bonnet

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A hat of cloth or straw, often held in place by ribbons tied under the chin, that is worn by women and children.
• noun Scots A brimless cap worn by men or boys.
• noun A removable metal plate over a machine part, such as a valve.
• noun Chiefly British The hood of an automobile.
• noun A windscreen for a chimney.
• noun A cover for a fireplace.
• noun Nautical A strip of canvas laced to a fore-and-aft sail to increase sail area.
• transitive verb To put a bonnet on.

from The Century Dictionary.

• To force the bonnet or hat over the eyes of, with the view of mobbing or hustling.
• To pull off the bonnet; make obeisance.
• To provide with an iron shield or bonnet: as, to bonnet a safety-lamp.
• noun A portion of a coal-seam left for a roof.
• noun A flat piece of wood on the top of a prop.
• noun plural Gas-coal or shale overlying a coal-seam or worked with it.
• noun The lid or cover of a hole by which access may be had to valves or other apparatus in a closed chamber.
• noun The protecting hood over the machinery or motor of a motor-vehicle, in front of the dashboard.
• noun 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.
• noun plural The spatter-dock, Nymphæa advena and the other species. See Nymphæa, 1.
• noun 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.
• noun A form of hat or head-covering worn by women out of doors.
• noun The cap, usually of velvet, within the metallic part of a crown, covering the head when the crown is worn.
• noun In fortification, a small work with two faces, having only a parapet with two rows of palisades about 10 or 12 feet apart.
• noun Nautical, an addition to a sail, or an additional part laced to the foot of a sail.
• noun A cast-iron plate covering the openings in the valve-chambers of a pump.
• noun 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.
• noun In mining, a shield or cover over the cage to protect the miners in case anything should fall down the shaft.
• noun A cowl or wind-cap for a chimney; a hood for ventilation.
• noun The hood over the platform of a railroad-car.
• noun A sliding lid or cover for a hole in an iron pipe.
• noun 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.
• noun 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.
• noun A local name in Florida of the yellow water-lily, Nuphar advena.

from the GNU version of the Collaborative International Dictionary of English.

• intransitive verb obsolete To take off the bonnet or cap as a mark of respect; to uncover.
• noun obsolete A headdress for men and boys; a cap.
• noun A soft, elastic, very durable cap, made of thick, seamless woolen stuff, and worn by men in Scotland.
• noun A covering for the head, worn by women, usually protecting more or less the back and sides of the head, but no part of the forehead. The shape of the bonnet varies greatly at different times; formerly the front part projected, and spread outward, like the mouth of a funnel.
• noun Anything resembling a bonnet in shape or use.
• noun (Fort.) A small defense work at a salient angle; or a part of a parapet elevated to screen the other part from enfilade fire.
• noun A metallic canopy, or projection, over an opening, as a fireplace, or a cowl or hood to increase the draught of a chimney, etc.
• noun A frame of wire netting over a locomotive chimney, to prevent escape of sparks.
• noun A roofing over the cage of a mine, to protect its occupants from objects falling down the shaft.
• noun In pumps, a metal covering for the openings in the valve chambers.
• noun (Naut.) An additional piece of canvas laced to the foot of a jib or foresail in moderate winds.
• noun The second stomach of a ruminating animal.
• noun Cant An accomplice of a gambler, auctioneer, etc., who entices others to bet or to bid; a decoy.
• noun (Automobiles), Brit. The metal cover or shield over the motor; predominantly British usage. In the U.S. it is called the hood.
• noun (Zoöl.) a name given, from their shape, to various species of shells (family Calyptræidæ).
• noun (Zoöl.) an East Indian monkey (Macacus sinicus), with a tuft of hair on its head; the munga.