noun
- an instrument that measures the speed of rotation of a shaft or disk, especially in a vehicle engine
Usage: automotive
Examples
- The tachometer showed the engine was running at 3,000 RPM.
- He watched the tachometer needle climb as he accelerated.
- The mechanic checked the tachometer to diagnose the engine problem.
- Most cars have a tachometer on the dashboard next to the speedometer.
- The tachometer helps drivers know when to shift gears in a manual transmission.
- The pilot monitored the aircraft engine’s tachometer during takeoff.