1) Atmospheric science 
Diathermancy (from `dia` through and `thermē` heat) is the property of some fluids that allows rays of light through them without itself being heated. A diathermanous fluid is thus `permeable` by heat.). Diathermany was first described by German physicist and chemist Heinrich Magnus in the 1800s. Atmospheric air is diathermanous; therefore,...
Transparency to heat.
• (n.) Alt. of Diathermaneity
The condition of being diathermic. ... (05 Mar 2000) ... 
Type: Term Pronunciation: dī′ă-thĕr′man-sē Definitions: 1. The condition of being diathermic.
Diathermancy is the property that is possessed in various degrees by different substances of transmitting radiant heat. Bodies that are equally transparent, that is, bodies which have equal power of transmitting rays of light, are very different in their power of transmitting heat rays. Thus a thin plate of glass and a thin plate of rock-salt may b...
diathermancy The property of being diathermic or diathermanous; perviousness to radiant heat; diathermaneity.
the property of transmitting heat as electromagnetic radiation.