The Collaborative International Dictionary of English v.0.48:

Pendulum \Pen"du*lum\, n.; pl. Pendulums. [NL., fr. L.
   pendulus hanging, swinging. See Pendulous.]
   A body so suspended from a fixed point as to swing freely to
   and fro by the alternate action of gravity and momentum. It
   is used to regulate the movements of clockwork and other
   machinery.
   [1913 Webster]

   Note: The time of oscillation of a pendulum is independent of
         the arc of vibration, provided this arc be small.
         [1913 Webster]

   Ballistic pendulum. See under Ballistic.

   Compensation pendulum, a clock pendulum in which the effect
      of changes of temperature of the length of the rod is so
      counteracted, usually by the opposite expansion of
      differene metals, that the distance of the center of
      oscillation from the center of suspension remains
      invariable; as, the mercurial compensation pendulum, in
      which the expansion of the rod is compensated by the
      opposite expansion of mercury in a jar constituting the
      bob; the gridiron pendulum, in which compensation is
      effected by the opposite expansion of sets of rods of
      different metals.

   Compound pendulum, an ordinary pendulum; -- so called, as
      being made up of different parts, and contrasted with
      simple pendulum.

   Conical pendulum or Revolving pendulum, a weight
      connected by a rod with a fixed point; and revolving in a
      horizontal circle about the vertical from that point.

   Pendulum bob, the weight at the lower end of a pendulum.

   Pendulum level, a plumb level. See under Level.

   Pendulum wheel, the balance of a watch.

   Simple pendulum or Theoretical pendulum, an imaginary
      pendulum having no dimensions except length, and no weight
      except at the center of oscillation; in other words, a
      material point suspended by an ideal line.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

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]