The term 'ROAD RIG ROD' is composed of four words, each with four letters. The first word, 'AXLE, ' refers to a shaft or ROD that connects two wheels of a vehicle and allows them to rotate together. It is an important part of the suspension system of a car, truck, or other vehicle. The second word, 'ROAD, ' refers to a paved or improved surface for travel, such as a highway or street. The third word, 'RIG, ' is a slang term for a vehicle, usually a truck, that is used for hauling cargo or equipment. Finally, the fourth word, 'ROD, ' is a long, thin piece of metal or other material, often used in construction or engineering. Together, these four words form the term 'ROAD RIG ROD, ' which is used to describe a vehicle that is used for hauling cargo or equipment on a paved surface.