Hōd'o-grāph, n.

n. [Gr. ὁδός, path, and γράφειν, to write or describe.] (Math.) A curve described by the moving extremity of a line the other end of which is fixed, this line being constantly parallel to the direction of motion of, and having its length constantly proportional to the velocity of, a point moving in any path; — sometimes used in investigations respecting central forces.