ta ‧ chom ‧ e ‧ ter /tæˈkɒmətə, tæˈkɒmɪtə $ -ˈkɑːmətər/ BrE AmE noun [countable] technical
[ Date: 1800-1900 ; Language: Greek ; Origin: tachos 'speed' + English -meter ]
a piece of equipment used to measure the speed at which the engine of a vehicle turns