Backstop and Stage set

Backstop noun - (baseball) a fence or screen (as behind home plate) to prevent the ball from traveling out of the playing field.

Stage set and backstop are semantically related. In some cases you can use "Stage set" instead a noun "Backstop".

Stage set noun - Representation consisting of the scenery and other properties used to identify the location of a dramatic production.

Backstop and stage set are semantically related. Sometimes you can use "Backstop" instead a noun phrase "Stage set".