the.com/tachometer
The gauge that tells you exactly how hard your engine is begging for mercy.
means An instrument measuring the rotational speed of an engine's crankshaft, usually in revolutions per minute.
from From Greek tachos, speed, plus metron, measure — literally a speed-counter, coined in the 1840s for spinning machinery before cars existed.
RedlineThe colored zone where revs invite engine suicide.
Naval cousinTachs once measured ship engine and propeller speeds.
Electric quirkMany EVs skip them entirely, having no idle rev.