Definitionen
1.NounAn 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.NounA 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.NounA reduction in bitumen softening point, sometimes called refluxing or overheating, in a relatively closed container.
4.NounPulverised material that falls back to earth after a nuclear explosion; fallout.
5.AdjectiveThat can be resorted to as a fallback."a fallback plan"
6.VerbMisspelling of fall back.