noun🔗ShareA device for measuring the revolutions per minute (RPMs) of a revolving shaft, as with the driveshaft of an automobile."The driver glanced at the tachometer to make sure the engine's RPMs were not too high. "devicemachinevehicletechnologyelectronicstechnicalChat with AIVocabulary GamePractice Reading
noun🔗ShareA device for measuring or indicating velocity or speed, as of blood, a river, a machine, etc."The mechanic checked the car engine's speed using a tachometer. "devicemachinetechnicalelectronicsvehiclephysicsscienceChat with AIVocabulary GamePractice Reading
