fallback

1. An act of falling back. (countable, uncountable) · A failure of one of the rocket's first-stage engines just after liftoff would result in a destructive pad fallback.· The black hole formed as a result of fallback of ejecta onto the neutron star initially created by the supernova explosion.
2. A backup plan or contingency strategy; an alternative which can be used if something goes wrong with the main plan; a recourse. (countable, uncountable) · As a fallback, I suppose we can use typewriters if the word processing system fails.
3. A reduction in bitumen softening point, sometimes called refluxing or overheating, in a relatively closed container. (countable, uncountable)
4. Pulverised material that falls back to earth after a nuclear explosion; fallout. (countable, uncountable)

Plural fallbacks