also: タコメータ
noun
tachometer; rev counter; RPM gauge
A device that measures the rotation speed of an engine or other rotating part, typically displayed in revolutions per minute (RPM). Common in automotive contexts.
車のタコメーターが急に上がった。
The car's tachometer suddenly shot up.
タコメーターを見ながらギアを変える。
I change gears while watching the tachometer.
Standard katakana spelling for tachometer.
Shorter variant, also common.
スピードメーター measures speed (km/h or mph), while タコメーター measures engine RPM.
From English 'tachometer', a device for measuring rotational speed.