cou·lisse 
(k-lēs)
(k-lēs)n.
1. A grooved timber in which something slides.
2.
a. A section of stage scenery placed in a wing of a theater.
b. The space between such pieces of scenery, through which an actor can make an entrance or exit.
c. A backstage area in a theater.
[French, from Old French (porte) couleice, sliding door; see PORTCULLIS.]