In baseball, a fence, prop. at least 90 feet behind the home base, to stop the balls that pass the catcher; also, the catcher himself.

In rounders, the player who stands immediately behind the striking base.

(baseball) a fence or screen (as behind home plate)

A small block on the bow end of the slide, which holds the seat on track.

(UK) The sliding seat position closest to the boat's bow.

In cricket, the longstop; also, the wicket keeper.

To support or bolster.

A device incorporated into the conveyor drive train that prevents belt roll-back in the event of power loss.

Something that will safely stop a bullet and prevent it from hitting anything else.

Alternative sources of energy which are assumed to become commercially available at some future date. Examples of potential backstops include solar, bio-mass, and fusion energy.

Backstop is a fictional character in the series.

act as a backstop