Hodograph
Pronunciation : Hod"o*graph
Part of Speech : n.
Etymology : [Gr.graph.] (Math.)
Definition : Defn: 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; -used in investigations respecting central forces.
Source : Webster's Unabridged Dictionary, 1913