Plain English Meaning
A way of measuring how heavy the air is pressing down on the ground. Higher numbers mean higher pressure; lower numbers mean lower pressure.
Full Definition
A unit of atmospheric pressure equal to one-thousandth of a bar, or 100 pascals. Standard sea level pressure is 1013.2 millibars, which corresponds to 29.92 inches of mercury. Millibars are used on weather charts and in aviation weather products to report station pressure, sea level pressure, and altimeter settings outside the United States.
Context Anchor
Seen when discussing altimeter settings, pressure, and international pressure .