conical surface

Conic \Con"ic\, Conical \Con"ic*al\, a. [Gr. ?: cf. F. conique.
   See {Cone}.]
   1. Having the form of, or resembling, a geometrical cone;
      round and tapering to a point, or gradually lessening in
      circumference; as, a conic or conical figure; a conical
      vessel.
      [1913 Webster]

   2. Of or pertaining to a cone; as, conic sections.
      [1913 Webster]

   {Conic section} (Geom.), a curved line formed by the
      intersection of the surface of a right cone and a plane.
      The conic sections are the parabola, ellipse, and
      hyperbola. The right lines and the circle which result
      from certain positions of the plane are sometimes, though
      not generally included.

   {Conic sections}, that branch of geometry which treats of the
      parabola, ellipse, and hyperbola.

   {Conical pendulum}. See {Pendulum}.

   {Conical projection}, a method of delineating the surface of
      a sphere upon a plane surface as if projected upon the
      surface of a cone; -- much used by makers of maps in
      Europe.

   {Conical surface} (Geom.), a surface described by a right
      line moving along any curve and always passing through a
      fixed point that is not in the plane of that curve.
      [1913 Webster]