isoline
nounUK /ˈaɪsəlaɪn/
US /ˈaɪsəlaɪn/
A line drawn on a map that connects places where something is the same.
The weather map uses an isoline to show where the temperature is exactly 20 degrees.
OTHER MEANINGS
2. A line on a map joining points of equal height, such as a contour line on a hiking map.
The hikers followed the isoline to stay at the same altitude.
3. A line connecting places with equal rainfall or equal temperature on a weather chart.
Meteorologists drew an isoline around the area expecting heavy rain.
4. Any line on a graph or chart linking points that share the same value.
The engineer plotted an isoline to show where pressure stays constant.