noun, feminine/ku.lis/plural: coulisses
coulisse (piece of timber); side of a stage, dressing room; slide or rail on which a drawer or window slides; background; underslide, underslide channel
“Comme nous avons pu le voir précédemment, le tiroir se pose sur la coulisse et le stabilise à l’arrière.” — As we have seen earlier, the drawer is placed on the rail which stabilizes it in the back.
From coulis.