adj. 1 of, relating to, or constituting a nucleus. 2 using nuclear energy (nuclear reactor). 3 having nuclear weapons. nuclear bomb a bomb involving the release of energy by nuclear fission or fusion or both. nuclear disarmament the gradual or total reduction by a State of its nuclear weapons. nuclear energy energy obtained by nuclear fission or fusion. nuclear family a couple and their children, regarded as a basic social unit. nuclear fission a nuclear reaction in which a heavy nucleus splits spontaneously or on impact with another particle, with the release of energy. nuclear force a strong attractive force between nucleons in the atomic nucleus that holds the nucleus together. nuclear-free free from nuclear weapons, power, etc. nuclear fuel a substance that will sustain a fission chain reaction so that it can be used as a source of nuclear energy. nuclear fusion a nuclear reaction in which atomic nuclei of low atomic number fuse to form a heavier nucleus with the release of energy. nuclear magnetic resonance the absorption of electromagnetic radiation by a nucleus having a magnetic moment when in an external magnetic field, used mainly as an analytical technique and in body imaging for diagnosis. °Abbr.: NMR, nmr. nuclear physics the physics of atomic nuclei and their interactions, esp. in the generation of nuclear energy. nuclear power 1 electric or motive power generated by a nuclear reactor. 2 a country that has nuclear weapons. nuclear reactor a device in which a nuclear fission chain reaction is sustained and controlled in order to produce energy. nuclear umbrella supposed protection afforded by an alliance with a country possessing nuclear weapons. nuclear warfare warfare in which nuclear weapons are used. nuclear waste any radioactive waste material from the reprocessing of spent nuclear fuel. nuclear winter obstruction of sunlight as a potential result of nuclear warfare, causing extreme cold.
[ NUCLEUS + -AR(1) ]