tachometer
Meaning
An instrument that measures the working speed of an engine, typically in revolutions per minute.
Structure
Usage
The pilot glanced at the tachometer to ensure the engine RPM was within the safe range.
A digital tachometer provides a more accurate reading than the old analog gauge.
Mechanics often use a handheld tachometer to diagnose engine performance issues.
Etymology
The word tachometer is a modern scientific compound, directly assembled from Greek roots in the 19th century. It combines takhos, meaning "speed" or "swiftness," with metron, meaning "a measure." The literal construction, "speed-measurer," perfectly describes its function. This term follows a classic pattern in technical English, where ancient Greek elements are repurposed to name precise instruments, with the meaning remaining transparently connected to its constituent parts.
Analysis
- tacho: From Greek takhos (speed, swiftness). A combining form denoting speed. - meter: From Greek metron (measure). A combining form denoting an instrument for measuring.