isogeothermyoudaoicibaDictYouDict[isogeotherm 词源字典]
"A line or surface on a diagram connecting points representing those in the interior of the earth having the same temperature", Mid 19th century: from iso- 'equal' + geo- 'earth' + Greek thermē 'heat'.[isogeotherm etymology, isogeotherm origin, 英语词源]