Source : Webster's Revised Unabridged Dictionary (1913)

Beacon \Bea"con\, n. [OE. bekene, AS. be['a]cen, b?cen; akin to
   OS. b?kan, Fries. baken, beken, sign, signal, D. baak, OHG.
   bouhhan, G. bake; of unknown origin. Cf. {Beckon}.]
   1. A signal fire to notify of the approach of an enemy, or to
      give any notice, commonly of warning.

            No flaming beacons cast their blaze afar. --Gay.

   2. A signal or conspicuous mark erected on an eminence near
      the shore, or moored in shoal water, as a guide to
      mariners.

   3. A high hill near the shore. [Prov. Eng.]

   4. That which gives notice of danger.

            Modest doubt is called The beacon of the wise.
                                                  --Shak.

   {Beacon fire}, a signal fire.

Source : WordNet®

beacon fire
     n : a fire (usually on a hill or tower) that can be seen from a
         distance [syn: {beacon}]