The tall, wide fence or net located behind the catcher's box In Major League Baseball, the backstop is located at least 60 feet away from home plate, but this distance varies in baseball on other levels The backstop separates foul territory from territory that is out of play, stops balls that go behind the catcher's box, and protects fans watching the game from behind home plate
To provide that last-resort support or security For example, in a rights offering you might hear: ABC Company will provide a 100% backstop of up to $100 million for any unsubscribed portion of the rights offering