Which instrument is used to measure wind speed?

The instrument used to measure wind speed is an anemometer. Anemometers typically consist of rotating cups or blades that catch the wind, and the speed at which they rotate can be correlated to wind speed. This allows meteorologists and other scientists to obtain accurate measurements necessary for weather forecasting, aviation, and various fields of study related to atmospheric science.

In contrast, a barometer is used to measure atmospheric pressure, an altimeter measures altitude or the height above a specific reference point (usually sea level), and a thermometer is used to measure temperature. Each of these instruments serves a distinct purpose related to atmospheric conditions but does not provide information about wind speed.