The Collaborative International Dictionary
Athermanous
Athermanous \A*ther"ma*nous\, a. [Gr. 'a priv. + qermai`nein to heat, qe`rma heat: cf. F. athermane.] (Chem.) Not transmitting heat; -- opposed to diathermanous.
Wiktionary
athermanous
a. Not transmitting heat.