'fallback' definitions:

Definition of 'fallback'

From: WordNet
noun
To break off a military action with an enemy [syn: disengagement, fallback, pullout]

Definition of 'fallback'

From: GCIDE
  • fallback \fall"back\, n.
  • 1. The act or process of falling back. [PJC]
  • 2. Something or someone to which one resorts as an alternative to a failed resource or method. [PJC]