• descent of radioactive particles from a nuclear explosion; radioactive particles; by-product, result
• fallout is the radiation that affects an area after a nuclear explosion.
• you can refer to the unpleasant consequences of an event or action as the fallout from it.
• protective structure designed to shield against radioactive residue or particles resulting from an atomic explosion
• particles charged with radio-active material that was formed as a result of a nuclear explosion
• particles charged with radioactive material that were created due to an atomic explosion