a tool for calculating the size of a path, composed of a wheel of understood circumference attached with a rod held in hand, and pressed along a surface, that is usually the floor or a floor. The number of times the wheel tends to make an entire circle multiplied by the circumference is a measure associated with the period of the path traversed. It might be used to determine distances on curved plus straight routes. A variant which registers the miles and rods traversed might be employed by surveyors.
a guitar for measuring the distance traveled by a wheeled automobile.