Homonym: Atomic (Nuclear)
"Atomic" refers to anything related to atoms, the basic building blocks of matter. Atoms consist of a nucleus, made up of protons and neutrons, surrounded by electrons. They combine in various ways to form molecules, which make up all substances in the universe, from gases to solids.
In the context of energy, "atomic" often relates to nuclear energy, which is produced through nuclear reactions involving atoms. This energy can be harnessed for electricity in nuclear power plants, where the process of nuclear fission splits atoms like uranium to release a significant amount of energy.