An anemometer is an instrument that measures the speed of wind.
It is used in ranging weather predictions and measure wind's pressure whether the wind velocity is high or low.
An anemometer has cups on it and when the wind blows, they spin around and one of the cups in different color so you can count how many times the colored cup goes round. If it is a high number then, that means that the wind speed is high whereas if it is a low number then, it means that the wind speed is low.