Decay energy is a term that refers to the energy released when a radioactive substance undergoes decay. There are several synonyms for the term "decay energy," including disintegration energy, radioactive energy, and nuclear energy. Disintegration energy refers to the energy released during the radioactive decay of an atomic nucleus. Radioactive energy is another synonym for decay energy, which is the energy released by a radioactive substance as it emits radiation. Lastly, nuclear energy is the energy released during nuclear fission or nuclear decay, and it is often used interchangeably with decay energy. These synonyms all describe the energy that is released when a radioactive substance undergoes decay.