athermancy

== English == === Etymology === See athermanous. === Noun === athermancy (uncountable) Inability to transmit radiant heat; impermeability to heat; the quality of being a good insulator. 1862, John Tyndall, "Further Researches on the Absorption and Radiation of Heat by Gaseous Matter", Philosophical Transactions, in Contributions to Molecular Physics in the Domain of Radiant Heat (1893), page 106 In fact the very experiments devised to show conductivity proved in a very striking manner the existence of athermancy, or opacity to radiant heat, in the case of a considerable number of gases.