When you get a divorce and, as a result, your friends have to choose sides and you are lonely, these are examples of the fallout of the divorce.
When a nuclear bomb is dropped on a city, the radioactive particles that remain in the air are an example of the fallout.
On 26 April 1986 the reactor number four at the Chernobyl Nuclear Power Plant located in the Soviet Union near Pripyat in Ukraine exploded. Further explosions and the resulting fire sent a plume of highly radioactive fallout into the atmosphere and over an extensive geographical area.
Psychological fallout in the shadow of terrorism, title of an article by Dr. Abraham Twerski, M.D. in .