What does speedometer mean?
A speedometer is an instrument fitted to a vehicle or machine that measures and displays how quickly it is moving. In cars, it normally reports speed in miles per hour or kilometres per hour, though digital displays have largely replaced traditional analogue gauges. A driver uses it to remain within speed limits, monitor whether the vehicle is accelerating or slowing, and avoid driving faster than the road conditions safely allow. The term can also describe an instrument that measures the rotational speed of machinery, although tachometer is more usual in that technical context. A speedometer should not be confused with an odometer: the former shows the current rate of travel, while the latter records the distance travelled. The word is formed from "speed" and the measuring suffix "-ometer," placing it alongside related instruments such as thermometer and odometer.
nounAn instrument that measures the speed of a vehicle or rotating component, usually by indicating its speed in miles or kilometres per hour.
- An instrument that measures and displays the speed of a vehicle, engine, or other moving mechanism.
"Her speedometer briefly showed ninety miles per hour before she slowed down."
"The speedometer indicated that the train was travelling at a steady speed."
"A faulty speedometer caused the car to fail its annual inspection."
The plural is used when referring to multiple speedometers, including instruments fitted to different vehicles.
"The mechanic tested both speedometers before returning the cars to their owners."
A speedometer tells you how fast you are going; an odometer remembers how far you have been.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does speedometer come from?
Speedometer combines "speed" with the suffix "-ometer," an English form of Greek metron, meaning "measure." The resulting name follows the established pattern of scientific measuring instruments such as thermometer and barometer. It entered English during the early twentieth century, as motor vehicles and other mechanical systems made accurate measurement of speed increasingly important.
How speedometer is actually used
In everyday British and American English, the term normally refers to the instrument fitted to a road vehicle. The form "speedometer gauge" is less common and may sound slightly redundant.
Easily confused with speedometer
A speedometer measures a vehicle's rate of travel, whereas an odometer records the total distance it has travelled.