Curve of quickest descent

Curve \Curve\, n. [See {Curve}, a., {Cirb}.]
   1. A bending without angles; that which is bent; a flexure;
      as, a curve in a railway or canal.
      [1913 Webster]

   2. (Geom.) A line described according to some low, and having
      no finite portion of it a straight line.
      [1913 Webster]

   {Axis of a curve}. See under {Axis}.

   {Curve of quickest descent}. See {Brachystochrone}.

   {Curve tracing} (Math.), the process of determining the
      shape, location, singular points, and other peculiarities
      of a curve from its equation.

   {Plane curve} (Geom.), a curve such that when a plane passes
      through three points of the curve, it passes through all
      the other points of the curve. Any other curve is called a
      {curve of double curvature}, or a {twisted curve}.
      [1913 Webster]