isopleth

noun

iso·​pleth ˈī-sə-ˌpleth 

1

: an isoline on a graph showing the occurrence or frequency of a phenomenon as a function of two variables

2

: a line on a map connecting points at which a given variable has a specified constant value

isoplethic

ˌī-sə-ˈple-thik 

adjective

Word History

Etymology

International Scientific Vocabulary is- + Greek plēthos quantity; akin to Greek plēthein to be full — more at full

First Known Use

1908, in the meaning defined at sense 1