1. the radioactive particles that settle to the ground after a nuclear explosion

Definition categories: substance, dust

2. any adverse and unwanted secondary effect

- a strategy to contain the fallout from the accounting scandal

Definition categories: phenomenon, consequence, effect, event, issue, outcome, result, upshot

Sentences with fallout as a noun:

- 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 [1].