What is designating, or pert. to, a reaction which occurs with absorption of heat; formed by such a reaction; as, an endothermic substance; -- opposed to exothermic called?

endothermic — Designating, or pert. to, a reaction which occurs with absorption of heat; formed by such a reaction; as, an endothermic substance; -- opposed to exothermic. (Webster's 1913.)

Sources