Isochasm
Pronunciation : I"so*chasm
Part of Speech : n.
Etymology : [Iso- + chasm.] (Phys. Geog.)
Definition : Defn: A line connecting places on the earth's surface at which there is the same mean frequency of auroras.
Source : Webster's Unabridged Dictionary, 1913
Merriam-Webster's Everyday Language Reference Set: Includes: The Merriam-Webster Dictionary, The Merriam-Webster Thesaurus, and The Merriam-Webster Vocabulary Builder