Specification Point 3.1: Know that chemical reactions in which heat energy is given out are described as exothermic, and those in which heat energy is taken in are described as endothermic
A reaction may involve multiple processes, and some of these may release heat, but as long as a reaction involves a net reduction in temperature, the reaction is endothermic. It's possible for this to happen because a chemical reaction always proceeds in a way that increases entropy. By contrast, exothermic reactions are those which release heat.