isobar
noun
- line of equal or constant pressure on a graph, plot, or map
- nucleide that has the same atomic mass as another but has a different number of protons
Wiktionary
noun
Etymology: From Ancient Greek ἴσος (ísos, “equal”) + βάρος (báros, “weight”), equivalent to iso- + bar-.
- A line drawn on a map or chart connecting places of equal or constant pressure.
- A set of points or conditions at constant pressure.
- Either of two nuclides of different elements having the same mass number.