speedometer

/spəˈdɑmədər/

/spiˈdɒmɪtə/

Other forms: speedometers

The device in a car that measures how fast you're going is the speedometer. Most speedometers can measure as much as 160 miles per hour — even though it's illegal to drive that fast in the U.S.

The traditional speedometer is a dial with a needle that moves to the right as you press on the gas pedal. Sometimes these devices simply display the digital numeric value of your speed, registering 50 and then 48 as the driver begins to slow down. Speedometers began to be a standard feature in automobiles around 1910, just a bit after the word was coined by adding the Greek-derived suffix -meter, or "a measure," to speed.

Definitions of speedometer

1. noun

   a meter fixed to a vehicle that measures and displays its speed
   synonyms: speed indicator

   types:

   machmeter

   speedometer for measuring the speed of an aircraft relative to the speed of sound

   type of:

   meter

   any of various measuring instruments for measuring a quantity