fall·out noun \ˈfȯ-ˌlau̇t\
: the often radioactive particles stirred up by or resulting from a nuclear explosion and descending through the atmosphere; also : other polluting particles (as volcanic ash) descending likewise
: descent (as of fallout) through the atmosphere
Seen & Heard
What made you want to look up fallout? Please tell us where you read or heard it (including the quote, if possible).