isobar

noun

iso·​bar ˈī-sə-ˌbär How to pronounce isobar (audio)
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

Illustration of isobar

Illustration of isobar
  • isobar 1

Examples of isobar in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
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

Word History

Etymology

probably borrowed from Greek isobarḗs "of equal weight," from iso- iso- + -barēs, adjective derivative of báros "weight, pressure"

First Known Use

circa 1864, in the meaning defined at sense 1

Time Traveler
The first known use of isobar was circa 1864

Rhymes for isobar

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Browse Nearby Words

isoamyl salicylate
isobar
isobarbaloin
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Cite this Entry

“Isobar.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/isobar. Accessed 28 Mar. 2025.

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Kids Definition

isobar

noun
iso·​bar ˈī-sə-ˌbär How to pronounce isobar (audio)
: a line drawn on a map to indicate areas having the same atmospheric pressure at a given time or for a given period
isobaric
ˌī-sə-ˈbär-ik
-ˈbar-
adjective

Medical Definition

isobar

noun
iso·​bar ˈī-sə-ˌbär How to pronounce isobar (audio)
: one of two or more atoms or elements having the same atomic weights or mass numbers but different atomic numbers

More from Merriam-Webster on isobar

Britannica.com: Encyclopedia article about isobar

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