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
Example Sentences
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 See More
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 See More Word History
Etymology
International Scientific Vocabulary is- + -bar (from Greek baros weight); akin to Greek barys heavy — more at grieve
First Known Use
circa 1864, in the meaning defined at sense 1
Kids Definition
isobar
noun
iso·bar ˈī-sə-ˌbär
: a line on a map to indicate areas having the same atmospheric pressure
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