Pronunciation: (nOO'klē-ur, nyOO'- or, by metathesis, -kyu-lur),[key] —adj. 1. pertaining to or involving atomic weapons: nuclear war. 2. operated or powered by atomic energy: a nuclear submarine. 3. (of a nation or group of nations) having atomic weapons.
4. of, pertaining to, or forming a nucleus.
5. of, pertaining to, or like the nuclear family: nuclear bonds.
—n.Informal. nuclear energy: switching to nuclear as a power source.