Which device is primarily used to measure atmospheric pressure?

The barometer is specifically designed to measure atmospheric pressure. It operates on the principle that changes in air pressure will affect the height of a column of liquid, typically mercury or water, or the movement of a flexible membrane. In meteorology, barometers are essential tools for weather forecasting, as fluctuations in atmospheric pressure indicate changes in weather conditions.

While a manometer is also a device that measures pressure, it is typically used for measuring the pressure of gases or liquids in a closed system rather than the atmospheric pressure. Thermometers and psychrometers, on the other hand, are used to measure temperature and humidity, respectively, and do not provide information about atmospheric pressure. Thus, the barometer stands out as the primary instrument for this specific purpose.