noun plural but singular or plural in construction
: an oil-well drilling apparatus that consists of a countershaft and drum and that is used for supplying driving power and lifting heavy objects
noun plural but singular or plural in construction
: an oil-well drilling apparatus that consists of a countershaft and drum and that is used for supplying driving power and lifting heavy objects
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012