Source : Webster's Revised Unabridged Dictionary (1913)

Apex \A"pex\, n.; pl. E. {Apexes}; L. {Apices}. [L.]
   1. The tip, top, point, or angular summit of anything; as,
      the apex of a mountain, spire, or cone; the apex, or tip,
      of a leaf.

   2. (Mining) The end or edge of a vein nearest the surface.
      [U.S.]

   {Apex of the earth's motion} (Astron.), that point of the
      heavens toward which the earth is moving in its orbit.

Apices \Ap"i*ces\, n. pl.
   See {Apex}.

Source : WordNet®

apices
     See {apex}

apex
     n 1: the highest point (of something); "at the peak of the
          pyramid" [syn: {vertex}, {peak}, {acme}]
     2: the point on the celestial sphere toward which the sun and
        solar system appear to be moving relative to the fixed
        stars [syn: {solar apex}, {apex of the sun's way}] [ant: {antapex}]
     [also: {apices} (pl)]