druse Syllabification: (druse)Pronunciation: /dro͞oz/Definition of druse noun 1 Geology a rock cavity lined with a crust of projecting crystals. the crust of crystals lining a rock cavity. 2 Botany a rounded cluster of calcium oxalate crystals found in some plant cells. Derivatives drusy adjective ( Geology)Origin: early 19th century: via French from German Druse 'weathered ore'druse in other Oxford dictionaries Definition of druse in the British & World English dictionary