tachometer
From Longman Dictionary of Contemporary EnglishRelated topics: Motor vehiclestachometerta‧chom‧e‧ter /tæˈkɒmɪtə $ -ˈkɑːmɪtər/ noun [countable] technical TTCa piece of equipment used to measure the speed at which the engine of a vehicle turnsExamples from the Corpustachometer• I am unable to find a supplier of an add on tachometer.Origin tachometer (1800-1900) Greek tachos “speed” + English -meter