Question

definition of background in scratch

Answer 1

backdrop is one out of possibly many frames, or backgrounds, of the Stage. It is located in the backdrops library. The Stage can change its look to any of its backdrops. They can be named, edited, created, and deleted, but the Stage must always have at least one backdrop; otherwise, the Stage would not have an image to resemble.

Answer 2

An image of the Stage with a sprite on it (the Scratch Cat). ... The Stage is the term for the background of the project, but can have scripts, backdrops (costumes), and sounds, similar to a sprite.