The crossword solution for the term 'Speed Reducer' is 'BUMP'. A speed reducer is a mechanical device used to reduce the speed of a rotating shaft. It works by using gears, brakes, or other methods to reduce the speed of the shaft and its connected components. BUMP is a type of speed reducer that uses a bumping mechanism to reduce the speed of the shaft. This mechanism involves a spring-loaded plunger that is pushed against the shaft, causing it to slow down.