In a single sliding application, one door leaf slides to the side of the opening. Therefore, two door leaves get splined (joined) together to slide as a single unit. You can find more wooden sliding door ideas in the following galleries.
A pair of doors sliding open from the center is considered a Bi-Parting door. As seen in the following wooden sliding door images, these carriage and barn doors slide on the same track and contact each other in the middle when closed.