The Collaborative International Dictionary of English v.0.48:

Surface \Sur"face`\, n. [F. See Sur-, and Face, and cf.
   Superficial.]
   1. The exterior part of anything that has length and breadth;
      one of the limits that bound a solid, esp. the upper face;
      superficies; the outside; as, the surface of the earth;
      the surface of a diamond; the surface of the body.
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            The bright surface of this ethereous mold. --Milton.
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   2. Hence, outward or external appearance.
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            Vain and weak understandings, which penetrate no
            deeper than the surface.              --V. Knox.
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   3. (Geom.) A magnitude that has length and breadth without
      thickness; superficies; as, a plane surface; a spherical
      surface.
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   4. (Fort.) That part of the side which is terminated by the
      flank prolonged, and the angle of the nearest bastion.
      --Stocqueler.
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   Caustic surface, Heating surface, etc. See under
      Caustic, Heating, etc.

   Surface condensation, Surface condenser. See under
      Condensation, and Condenser.

   Surface gauge (Mach.), an instrument consisting of a
      standard having a flat base and carrying an adjustable
      pointer, for gauging the evenness of a surface or its
      height, or for marking a line parallel with a surface.

   Surface grub (Zool.), the larva of the great yellow
      underwing moth (Triphoena pronuba). It is often
      destructive to the roots of grasses and other plants.

   Surface plate (Mach.), a plate having an accurately dressed
      flat surface, used as a standard of flatness by which to
      test other surfaces.

   Surface printing, printing from a surface in relief, as
      from type, in distinction from plate printing, in which
      the ink is contained in engraved lines.
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The Collaborative International Dictionary of English v.0.48:

Heating \Heat"ing\ (h[=e]t"[i^]ng), a.
   That heats or imparts heat; promoting warmth or heat;
   exciting action; stimulating; as, heating medicines or
   applications.
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   Heating surface (Steam Boilers), the aggregate surface
      exposed to fire or to the heated products of combustion,
      esp. of all the plates or sheets that are exposed to water
      on their opposite surfaces; -- called also fire surface.
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