We don't have synonyms for isograd yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are isogram.
(n) :
(geology) A line, either on a map or the surface of the Earth, joining points at which metamorphism reached similar pressures and temperatures; actually the intersection of a surface and that of the Earth.
(n) :
(geology) A line, either on a map or the surface of the Earth, joining points at which metamorphism reached similar pressures and temperatures; actually the intersection of a surface and that of the Earth.