- a line on a map connecting points having equal barometric pressure at a given reference altitude, commonly sea level, over a given period or at a given time
- any atom that has the same atomic weight (or mass number) as another atom but a different atomic number (Ex.: carbon-14 and nitrogen-14)
Origin of isobarfrom iso- + Classical Greek baros, weight
- A line on a weather map connecting points of equal atmospheric pressure. Also called isopiestic .
- Any of two or more kinds of atoms having the same atomic mass but different atomic numbers.
Origin of isobariso- Greek baros weight ; see gwerə-1 in Indo-European roots.
- In meteorology, the term isobar most often refers to a line drawn through connected points of equal atmospheric pressure on a given reference surface — such as a constant height surface (notably mean-sea-level on surface charts), the vertical plane of a synoptic cross section, or a layer of the air unaffected by surface heating or cooling. The pattern of isobars has always been a main feature of surface chart analysis. (See Surface weather analysis on Wikipedia.) Until recently it was standard procedure to draw isobars at 3-millibar intervals. However, the advent of constant pressure charts for upper-air analysis has brought about the use of 4-millibar intervals to simplify the conversion from surface isobars to 1,000-millibar contour lines.
From Ancient Greek ἴσος (isos, “equal”) + βάρος (baros, “weight”)