Which instrument is used specifically for measuring atmospheric pressure?

The barometer is the instrument specifically designed to measure atmospheric pressure. It operates on the principle that changes in atmospheric pressure can be detected and quantified through the movement of a liquid (in traditional mercury barometers) or through the use of electronic sensors in more modern designs. Barometers are crucial in meteorology as they help predict weather changes; for example, falling pressure indicates that a storm may be approaching, while rising pressure often suggests improving weather conditions.

In contrast, other instruments serve different purposes. A hygrometer measures humidity, an anemometer is used to determine wind speed, and a thermometer measures temperature. Each of these tools is essential for various aspects of weather observation and forecasting, but none are suitable for measuring atmospheric pressure like the barometer.