fallback

noun

1. an act or instance of falling back.
2. something or someone to turn or return to, especially for help or as an alternative: His teaching experience would be a fallback if the business failed.

adjective

3. Also fall-back. of or designating something kept in reserve or as an alternative: The negotiators agreed on a fallback position.

n.

also fall-back; 1767 as a type of chair; 1930 as “a position to be used in an emergency;” from fall (v.) + back (adv.).