House left/right are from the audience's perspective

In theatre, blocking is the exact positioning of actors on a stage during a performance. The word comes from practices used by theatre directors of the 19th century, who worked out the staging of a scene on a model stage using wooden blocks to represent each of the actors. Today, the director usually determines blocking during rehearsal. They tell the actors where they should move for the proper dramatic and lighting effect, and to ensure that the audience can see everything.