• WordNet 3.6
    • n isopleth a line drawn on a map connecting points having the same numerical value of some variable
    • ***
Century Dictionary and Cyclopedia
    • n isopleth A line, on a chart, showing the occurrence of equal quantities, conditions, or frequencies of any phenomenon in its relation to two independent coordinates. This term was first used by Vogler (1880), but the lines themselves had long been familiar.
    • ***


In science:

The main problem with the CGCG, as immediately pointed out by Abell12 , was that the sizes of Zwicky’s clusters were distance-dependent, since they were defined within the isopleth contour that represents twice the field density.
From Messier to Abell: 200 years of science with galaxy clusters
Isopleths representing the position of the fire front at successive time intervals were fitted to the grid of timer data for each plot using a contouring routine based on a distanceweighted least squares algorithm.
A review of wildland fire spread modelling, 1990-present 2: Empirical and quasi-empirical models