backdrop
exposisiton
The whole area is simply called "backstage." The sides, to be specific, are called the "wings."
Stage Direction
Stage
a costume.
It is called an exit. Plural (multiple actors leave) is exeunt.
it was called the centre and then around the sides was where the chorus stood
These are usually called 'asides'.
The actors at the globe theater went to the tiring house to change their costumes. The Tiring house was a three structure behind the stage.
Advantage- everyone could see you Disadvantage- expensive and was also not conducive to either seeing or hearing the actors on stage.
stage directions
The chorus does. In Greek drama that is a group of actors who come on stage and set the scene, but in Shakespeare it is one person.