speedometer

noun

1. An instrument located within the dashboard of a vehicle that measures and indicates the current speed of the vehicle.

   “Although it might be thought that drivers would naturally refer constantly to the speedometer, older drivers who come to diesel driving after years of steam experience without the help of speedometers, as well as those on steam engines which have been equipped with speedometers in recent years, have not accustomed themselves to the constant use of this instrument.”

   “But even Apple, the company that cast aside tradition when it reinvented phones, music players and headphones, bows to convention when it comes to speedometers. It displayed a classically-styled speedometer that reached 160 mph, an auto industry norm. That’s nearly twice the highest posted speed limit in the United States, 85 mph, on a stretch of highway in Texas. Why do our speedometers stretch to a speed that’s illegal, and only race-car drivers will ever reach?”

2. Such a device incorporating an odometer.