Illustration of isobar
- isobar 1
isobar
noun
iso·bar
ˈī-sə-ˌbär 
1
: an imaginary line or a line on a map or chart connecting or marking places of equal barometric pressure
2
: one of two or more atoms or elements having the same atomic weights or mass numbers but different atomic numbers
Examples of isobar in a Sentence
Recent Examples on the Web
Trying to predict the unpredictable is why meteorologists often wind up at the isobar after work.
—
Star Tribune, 15 July 2021
But the local pressure gradient was most intense along the New England coast, where isobars were extremely crowded together, driving 40 to 50 mph sustained winds.
—Jeff Halverson, Washington Post, 5 Mar. 2018
The next image shows the incredible pressure gradient (change in pressure over distance, revealed by contour lines called isobars).
—Jeff Halverson, Washington Post, 5 Mar. 2018
From the two figures above, note that the isobars became spread apart and fewer in number (the signature of weakening) and the eyewall’s intense ring of rain diminished significantly.
—Jeff Halverson, Washington Post, 31 Aug. 2017
Dear Tom, What determines how isobars are drawn on weather maps?
—Tom Skilling, chicagotribune.com, 13 May 2017
Dear Tom,
What determines how isobars are drawn on weather maps?
—Tom Skilling, chicagotribune.com, 13 May 2017
Isobars help the meteorologist locate frontal boundaries because fronts are located in troughs of low pressure.
—Tom Skilling, chicagotribune.com, 13 May 2017
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Star Tribune, 15 July 2021
But the local pressure gradient was most intense along the New England coast, where isobars were extremely crowded together, driving 40 to 50 mph sustained winds.
—Jeff Halverson, Washington Post, 5 Mar. 2018
The next image shows the incredible pressure gradient (change in pressure over distance, revealed by contour lines called isobars).
—Jeff Halverson, Washington Post, 5 Mar. 2018
From the two figures above, note that the isobars became spread apart and fewer in number (the signature of weakening) and the eyewall’s intense ring of rain diminished significantly.
—Jeff Halverson, Washington Post, 31 Aug. 2017
Dear Tom, What determines how isobars are drawn on weather maps?
—Tom Skilling, chicagotribune.com, 13 May 2017
Dear Tom,
What determines how isobars are drawn on weather maps?
—Tom Skilling, chicagotribune.com, 13 May 2017
Isobars help the meteorologist locate frontal boundaries because fronts are located in troughs of low pressure.
—Tom Skilling, chicagotribune.com, 13 May 2017
Cite this Entry
“Isobar.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/isobar. Accessed 11 Jul. 2025.
Copy CitationKids Definition
isobar
noun
iso·bar
ˈī-sə-ˌbär
: a line drawn on a map to indicate areas having the same atmospheric pressure at a given time or for a given period
isobaric
adjective
ˌī-sə-ˈbär-ik
-ˈbar-
Medical Definition
isobar
noun
iso·bar
ˈī-sə-ˌbär
: one of two or more atoms or elements having the same atomic weights or mass numbers but different atomic numbers
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