The term 'ROTATING CYLINDER' can be broken down into two parts: 'ROTATING' and 'CYLINDER'. The first part, 'ROTATING', refers to the act of turning around a central point or axis. The second part, 'CYLINDER', is a three-dimensional shape with two parallel bases that are connected by a curved surface. When combined, the term 'ROTATING CYLINDER' describes an object that is shaped like a CYLINDER and is able to rotate around its central axis. The crossword solution for this term is 'ROLLER', which is a device that is used to roll or move objects along a flat surface.