Isogeotherm
Pronunciation : I`so*ge"o*therm
Part of Speech : n.
Etymology : [Iso- + Gr. gh^ the earth + qe`rmh heat.] (Phys. Geog.)
Definition : Defn: A line or curved surface passing beneath the earth's surface through points having the same mean temperature.
Source : Webster's Unabridged Dictionary, 1913