Barometer (noun)

1. An instrument used to measure atmospheric pressure.
2. A device used to measure the weight of the air, which is used to predict changes in the weather.
3. An instrument that determines the weight of the atmosphere and thus the pressure of the air.

Origin:

The word barometer comes from the greek words "baros" meaning weight, and "metron" meaning measure. it was first used in the early 17th century to refer to an instrument used for measuring atmospheric pressure.

Examples:

1. The barometer is showing that a storm is coming.
2. Barometer is an instrument used in meteorology to measure atmospheric pressure.
3. He uses a barometer to predict the weather.
4. The barometer is a device for measuring atmospheric pressure.
5. The barometer is used to indicate the change in weather conditions.