The term SUFFIX FOR SWITCH has a crossword solution of EROO, which is a four-letter word. EROO is a suffix that is commonly used to refer to a switch or a device that can be turned on and off. It is derived from the Latin word 'erigere, ' which means 'to raise up.' This suffix is often used in electrical engineering and computer science to refer to a switch or a device that can be activated or deactivated.