Source : Webster's Revised Unabridged Dictionary (1913)

Rubble \Rub"ble\, n. [From an assumed Old French dim. of robe
   See {Rubbish}.]
   1. Water-worn or rough broken stones; broken bricks, etc.,
      used in coarse masonry, or to fill up between the facing
      courses of walls.

            Inside [the wall] there was rubble or mortar.
                                                  --Jowett
                                                  (Thucyd.).

   2. Rough stone as it comes from the quarry; also, a
      quarryman's term for the upper fragmentary and decomposed
      portion of a mass of stone; brash. --Brande & C.

   3. (Geol.) A mass or stratum of fragments or rock lying under
      the alluvium, and derived from the neighboring rock.
      --Lyell.

   4. pl. The whole of the bran of wheat before it is sorted
      into pollard, bran, etc. [Prov. Eng.] --Simmonds.

   {Coursed rubble}, rubble masonry in which courses are formed
      by leveling off the work at certain heights.

Source : WordNet®

rubble
     n : the remains of something that has been destroyed or broken
         up [syn: {debris}, {dust}, {junk}, {detritus}]