A tachometer is an instrument in a car or an airplane which shows the speed of the engine.
[mainly US]
The tachometer registers a rather high 3,000 rpm at 70 mph.
tachometer in British English
(tæˈkɒmɪtə)
noun
any device for measuring speed, esp the rate of revolution of a shaft. Tachometers (rev counters) are often fitted to cars to indicate the number of revolutions per minute of the engine
Derived forms
tachometric (ˌtækəˈmɛtrɪk) or tachometrical (ˌtachoˈmetrical)
adjective
tachometrically (ˌtachoˈmetrically)
adverb
tachometry (taˈchometry)
noun
tachometer in American English
(tæˈkɑmətər; təˈkɑmətər)
noun
a device that indicates or measures the rate of rotation of a revolving shaft
Word origin
< Gr tachos, speed (< tachys: see tachy-) + -meter
Examples of 'tachometer' in a sentence
tachometer
`Several times during the wild ride over the open highway from Dulles to the city, Loren swept the tachometer needle into the red.