cub·ism also Cub·ism  (kyōō'bĭz'əm)  n. A nonobjective school of painting and sculpture developed in Paris in the early 20th century, characterized by the reduction and fragmentation of natural forms into abstract, often geometric structures usually rendered as a set of discrete planes. cub'ist n., cu·bis'tic adj., cu·bis'ti·cal·ly adv. |