1) Isarithm 2) Isobar 3) Isochrone 4) Isogram 5) Isohel 6) Isotherm 7) Isothermic 1) Isarithm 2) Isogram 3) Line 
contour line joining points corresponding to similar values. Often used to plot yield-per-recruit values on a graph showing the changes as a function of size-at-first-capture and fishing mortality.
line connecting points of equal aspect of climate
(from the article `timberline`) ...over water in the Southern Hemisphere, this timberline exists only in the Northern Hemisphere. It crosses northern Siberia, Alaska, and Canada, ...
A line on a Cartesian nomogram consisting of all points that represent a particular value of a variable; e.g., an isobar is an isopleth for a particular pressure. ... (05 Mar 2000) ... 
General term for a line of equal value of some quantity. Isobars, isotherms, etc. all are examples of isopleths.
Type: Term Pronunciation: ī′sō-pleth Definitions: 1. A line on a cartesian nomogram consisting of all points that represent a particular value of a variable; an isobar is an isopleth for a particular pressure.
contour line joining points corresponding to similar values. Often used to plot yield-per-recruit values on a graph showing the changes as a function of size-at-first-capture and fishing mortality.
isopleth, isoplethic Equal in quantity.
The line or area represented by an isoconcentration. 
a line drawn on a map through all points having the same numerical value, as of a population figure or geographic measurement. Also called