The term 'clutch warmer' refers to a device used in automobiles to heat up the clutch plate, which is part of the transmission system. The device is usually powered by electricity and helps to reduce wear and tear on the clutch plate by warming it up before use. The crossword solution for this term is 'HEN, ' which is a reference to the fact that the device is often referred to as a 'chicken coop' due to its shape.