A backstop is a barrier that stops something from going too far. In baseball, the backstop is the fence or screen behind home plate that keeps wild pitches and foul balls from flying into the stands. Without it, balls would scatter everywhere and spectators might get hurt.

The word has expanded beyond baseball. In everyday conversation, a backstop is anything that catches problems or prevents failure. Parents might serve as a financial backstop for their college student, ready to help if unexpected expenses arise. A business might keep a backstop plan in case its main strategy doesn't work. Firefighters create backstop barriers to prevent wildfires from spreading beyond a certain point.

When you create a backstop, you're thinking ahead about what could go wrong and setting up protection before you need it. A student might create a backstop by studying extra material before a test, just in case the teacher asks harder questions than expected. A good backstop works quietly in the background. You hope you never need it, but you're grateful it's there when something goes wrong.