Is it farther or further?
1884, from French endothermique (1879); see endo- + thermal.
endothermic en·do·ther·mic (ěn'dō-thûr'mĭk) or en·do·ther·mal (-məl)adj.
Of or relating to a chemical reaction during which there is absorption of heat.
Of or relating to an endotherm; warm-blooded.
Relating to a chemical reaction that absorbs heat. Compare exothermic.