D defs.my
Entry 2 senses Webster, 1913

fallback

/fôl'-băkˌ/ · fall·back · IPA /ˈfɔːl.bæk/
01 n. The act or process of falling back.
  1. 1.
    The act or process of falling back.
  2. 2.
    Something or someone to which one resorts as an alternative to a failed resource or method.