The story
From iso- + the first element of phenology, the word having been first used to refer to phenological phenomena.
Etymology from Wiktionary, CC BY-SA 4.0.
isophene
Today it means: A line (on a map, etc.) joining places where a particular biological phenomenon is exhibited in the same way, such as where plants flower at the same time (an isanthesic) or where the same proportion of clines is found. Full definition →