isobar

American  

[ahy-suh-bahr] / ˈaɪ səˌbɑr /

noun

1. Meteorology. a line drawn on a weather map or chart that connects points at which the barometric pressure is the same.

2. Physics, Chemistry. Also isobare one of two or more atoms having equal atomic weights but different atomic numbers.

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isobar British  

/ ˈaɪsəʊˌbɑː /

noun

1. a line on a map connecting places of equal atmospheric pressure, usually reduced to sea level for purposes of comparison, at a given time or period

2. physics any of two or more atoms that have the same mass number but different atomic numbers Compare isotope

   tin-115 and indium-115 are isobars

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isobar Scientific  

/ ī′sə-bär′ /

1. A line drawn on a weather map connecting places having the same atmospheric pressure. The distance between isobars indicates the barometric gradient (the degree of change in atmospheric pressure) across the region shown on the map. When the lines are close together, a strong pressure gradient is indicated, creating conditions for strong winds. When the lines are far apart, a weak pressure gradient is indicated and calm weather is forecast.

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Other Word Forms

• isobarism noun

Etymology

Origin of isobar

First recorded in 1860–65; from Greek isobarḗs “of equal weight,” from ísos ( iso- ( def. ) ) + báros “weight” ( bar ³ ( def. ) )

Example Sentences

When we ran out of ways to tart up the lowly isobar, we went off-planet.

From Washington Post • Jan. 4, 2018

The center of the nearby low-pressure system has a barometric pressure of 994 millibars, which is marked by an isobar and underlined.

From Time Magazine Archive

If a line were drawn through all points on the surface of the earth having an equal barometric pressure at the same time, such a line would be called an isobar.

From General Science by Clark, Bertha M.

The weather has been variable, with cryptoconchoidal deflections of a solid reverberating isobar previously tested in a solution of zinc and soda-water.

From Punch, or the London Charivari, Volume 99, July 19, 1890 by Various

Now, Mr. Tighe, you can see from the map that the barometric pressure, the isobar, running through this part of the country shows a barometric pressure of 30.30.

From The Boy with the U. S. Weather Men by Rolt-Wheeler, Francis