Exothermic describes a process that releases energy to its surroundings, usually as heat. As a result, the surroundings warm and the products store less energy than the reactants. Combustion and the formation of chemical bonds are exothermic, in contrast to endothermic processes, which absorb energy.

放热形容向环境释放能量(通常以热量形式)的过程。其结果是环境变暖,产物储存的能量比反应物少。燃烧和化学键的形成是放热的;与之相对,吸热过程则吸收能量。