HODOGRAPH
Etymology
Noun
hodograph (plural hodographs)
(physics, maths) A curve described by the moving extremity of a line whose other end 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: Wiktionary
Hod"o*graph, n. Etym: [Gr.graph.] (Math.)
Definition: 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 Edition