back-stop

Noun

backstop (plural backstops)

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 Express, 7 June 2018
3. A wall or fence behind home plate.
4. (slang) A catcher; the position of catcher.
   • Bench may be the greatest catcher subjectively, but he's not statistically. Statwise, Yogi Berra is the all-time backstop, regardless of which measure you prefer. Berra's Total-Z is one-third of a standard deviation higher than Bench's, and his Core-Z average is a point better.2002, James F. Vail, Outrageous Fortune: What's Wrong with Hall of Fame Voting and How to Make It Statistically Sound, Jefferson, NC: McFarland & Company, →ISBN, page 143
5. The player who stands immediately behind the striking base.
6. (dated) The longstop.

See all 11 meanings of backstop