The Collaborative International Dictionary
Isotherombrose
Isotherombrose \I*soth`er*om"brose\, n. [Iso- + Gr. qe`ros summer + 'o`mbros rain.] (Phys. Geog) A line connecting or marking points on the earth's surface, which have the same mean summer rainfall.
Wiktionary
isotherombrose
n. (context geography English) A line connecting or marking points on the Earth's surface that have the same mean summer rainfall.