1911 Encyclopædia Britannica/Rubble
RUBBLE, broken stone, of irregular size and shape. This word is closely connected in derivation with "rubbish," which was formerly applied to what we now call "rubble." The earlier Middle English form was robeux or robows. It would appear that the original is an old Fr. robel. Roba (older form robba) is found in Italian in the sense of refuse, trash. Robba is explained by Florio as a gown, or mantle, robe, wealth, goods, trash. The original sense was "spoil." Thus, "robe," "rob," "rubbish" and "rubble" are all cognate.
"Rubble-work" is a name applied to several species of masonry (q.v.). One kind, where the stones are loosely thrown together in a wall between boards and grouted with mortar almost like concrete, is called in Italian muraglia di getto and in French bocage. Work executed with large stones put together without any attempt at courses is also called rubble.