tachometer
ta-cho-me-ter
noun
An instrument measuring the rotational speed of an engine's crankshaft in revolutions per minute.
"The driver watched the tachometer as the engine revved."
Thesaurus
Synonyms: tach
ta-cho-me-ter
An instrument measuring the rotational speed of an engine's crankshaft in revolutions per minute.
"The driver watched the tachometer as the engine revved."
Synonyms: tach