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: Webster's Revised Unabridged Dictionary (1913)