A speedometer is a device that measures the instantaneous speed of a land vehicle.
Now universally fitted to motor vehicles, they started to be available as options in the 1900s, and as standard equipment from about 1910 onwards.[1]
Speedometers for other vehicles have specific names and use other means of sensing speed. For a boat, this is a pit log. For an aircraft, this is an Airspeed indicator.
The speedometer was invented by the Croatian Josip Belušic in 1888, and was originally called a velocimeter.