Definition of "backstop" in English

noun

1. An object or a person put in the rear or in the back of something to reinforce, hold, support.

2. A default arrangement that holds if all else fails.

   • Irish prime minister Leo Varadkar, this morning, said a time-limited backstop would be unacceptable, and has previously promised to vote down the UK’s Brexit withdrawal deal unless it features a satisfactory backstop.
   • "The 2½ years since have been about hammering home these points in any European capital that would listen. And in spite of capacity-sapping talks on the first point – Brexit, border and backstop – the Department of Foreign Affairs and other government departments have been working quietly to make good on the second.

3. (baseball) A wall or fence behind home plate.

4. (baseball, slang) A catcher; the position of catcher.

5. (rounders) The player who stands immediately behind the striking base.

6. (cricket, dated) The longstop.

7. (cricket, dated) The wicket-keeper.

8. (espionage) Something serving to bolster or support a cover story etc.

verb

1. (transitive) To serve as backstop for.

2. (transitive) To bolster, support.