"Desired engine RPM" refers to the speed at which an engine is set to run by the operator or computer system. Some synonyms for desired engine RPM include: 1. Target RPM 2. Optimal RPM 3. Preferred RPM 4. Required RPM 5. Set RPM These synonyms can be used interchangeably to describe the RPM at which an engine should be running, depending on the context. For example, a car may have a "preferred RPM" for cruising on the highway, while a machinery operator may need to maintain a "required RPM" to ensure optimal performance. No matter which synonym is used, they all refer to the specific speed that the engine should be running at to achieve its intended function.