What is the X in X-mas?
name of a high, barren limestone region around Trieste; used by geologists from 1894 to refer to similar landforms. The word is the German form of Slovenian kras.
terrain usually characterized by barren, rocky ground, caves, sinkholes, underground rivers, and the absence of surface streams and lakes. It results from the excavating effects of underground water on massive soluble limestone. The term originally applied to the Karst, a limestone area on the Dalmatian coast on the Adriatic Sea, but has been extended to mean all areas with similar features.