Turkish form for a vertical or steepsided depression or shaft in karst, often formed by collapse of roof of an underground cave or cavern. When the depression contains a lake of pond, it is known as 'sulu obruk' or 'obruk golu'. When it is dry, it is called 'kuru obruk' or just 'obruk'. Synonyms: (French.) obruk; (German.) Schlot; (Greek.) 'obruk' (kathetos karstikos lakkos); (Italian.) pozzo carsico; (Spanish.) torca; (Turkish.) obruk; (Yugoslavian.) jama. See cenote, dolina, jama, pit, shaft, sinkhole.