fallback

noun

1. (countable, uncountable)An act of falling back.

   “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. (countable, uncountable)A backup plan or contingency strategy; an alternative which can be used if something goes wrong with the main plan; a recourse.

   “As a fallback, I suppose we can use typewriters if the word processing system fails.”

3. (countable, uncountable)A reduction in bitumen softening point, sometimes called refluxing or overheating, in a relatively closed container.
4. (countable, uncountable)Pulverised material that falls back to earth after a nuclear explosion; fallout.

   “Particle size distributions of fallback and ejecta were determined principally by mechanical sieving and weighing.”

adj

1. (not-comparable)That can be resorted to as a fallback.

   “a fallback plan”

verb

1. (alt-of, misspelling)Misspelling of fall back.