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