An instrument for measuring atmospheric pressure. / (figuratively, by extension) Anything used as a gauge or indicator.

plural of barometer

A barometer in which variations in pressure are measured using a partially evacuated capsule whose sides move in and out.

A mercury barometer

A barometer which indicates the atmospheric pressure by measuring the height of a column of mercury in a vertical, evacuated tube.

plural of aneroid barometer

plural of mercury barometer

plural of Torricellian barometer

A barometer in which water is substituted for mercury.

plural of water barometer