rubble

Etymology

From Middle English rouble, rubel, robel, robeil, from Anglo-Norman *robel (“bits of broken stone”). Presumably related to rubbish, originally of same meaning (waste material, bits of stone, rubble). Ultimately presumably from Old Norse rubba (“to huddle, crowd together, heap up", possibly also "to rub, scrape”), from Proto-Germanic *rubbōną (“to rub, scrape”), related to Proto-Germanic *reufaną (“to tear”), *raubōną (“to rob, steal, plunder”), perhaps via Old French robe (English rob (“steal”)) in sense of “plunder, destroy”; see also Middle English, Middle French -el.

noun

1. The broken remains of an object, usually rock or masonry.
   Floods in northern India, mostly in the small state of Uttarakhand, have wrought disaster on an enormous scale.[…]Rock-filled torrents smashed vehicles and homes, burying victims under rubble and sludge. 2013-06-29, “High and wet”, in The Economist, volume 407, number 8842, page 28
2. (geology) A mass or stratum of fragments of rock lying under the alluvium and derived from the neighbouring rock.
   The overlying beds are composed of such calcareous rubble and flints, rudely stratified 1855, Sir Charles Lyell, A Manual of Elementary Geology
3. (UK, dialect, in the plural) The whole of the bran of wheat before it is sorted into pollard, bran, etc..