Pronunciation: (rub'ul or, for 3, 4, rOO'bul), [key]
1. broken bits and pieces of anything, as that which is demolished: Bombing reduced the town to rubble.
2. any solid substance, as ice, in irregularly broken pieces.
3. rough fragments of broken stone, formed by geological processes, in quarrying, etc., and sometimes used in masonry.
4. masonry built of rough fragments of broken stone.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.