Wiktionary
back projection
n. (context film English) A cinematic technique in which live action is filmed in front of a screen on which the background action or a background scene is projected.
Usage examples of "back projection".
One third had the e split door to the outer world (back projection of the stable yard), one portion contained a manger and water bucket.
Condensation was forming on the windscreen and the crane swung its skeletonic arm through the floodlights insubstantially, like a back projection on frosted glass.