ClipArt ETC
"Fifth wheel, a horizontal plate, bent to form a whole or part of a circle, placed on the forward axle of a carriage. It is designed to support the fore part of the body while allowing it to turn freely in a horizontal plane." Today, the fifth wheel is used in coupling of trailers and towing trucks. -Whitney, 1911

Fifth Wheel

"Fifth wheel, a horizontal plate, bent to form a whole or part of a circle, placed on the forward axle…

"Fifth wheel, a horizontal plate, bent to form a whole or part of a circle, placed on the forward axle of a carriage. It is designed to support the fore part of the body while allowing it to turn freely in a horizontal plane." Today, the fifth wheel is used in coupling of trailers and towing trucks. -Whitney, 1911

Fifth Wheel

"Fifth wheel, a horizontal plate, bent to form a whole or part of a circle, placed on the forward axle…