Definition

1. Noun:
   • A unit of atmospheric pressure: A millibar is a metric unit of pressure equal to one thousandth (1/1000) of a bar. It is commonly used in meteorology to measure atmospheric pressure.

Usage

• The millibar is used to quantify atmospheric pressure in weather reports, scientific studies, and aviation.
• Standard atmospheric pressure at sea level is approximately 1013 millibars.

Examples

• Noun:
  • The weather map shows a low-pressure system of 990 millibars moving east.
  • Meteorologists reported a rapid pressure drop of 20 millibars as the storm approached.

Advanced Usage

• "to fall/rise by X millibars": Used to describe changes in atmospheric pressure over time.
  • The barometric pressure fell by 15 millibars in just three hours, indicating the storm's intensity.

Variants and Related Words

• Bar (n): The base unit; 1 bar = 1000 millibars.
• Hectopascal (hPa) (n): A modern, equivalent unit of pressure; 1 millibar is exactly equal to 1 hectopascal. In modern meteorology, hectopascals have largely replaced millibars, but the values are numerically identical.

Synonyms

• Hectopascal (hPa): The SI-derived unit that is equivalent to the millibar.

Noun

1. a unit of atmospheric pressure equal to one thousandth of a bar
   • atmospheric pressure at sea level is 1013 millibars