What do we mean by “piece”?

In the diagram below, you see the various individual pieces that can make up a sectional. Notice that in this example, when you are facing the sectional, the chaise piece’s arm can be found on the right side. Thus, we call this a Right Arm Facing (RAF) Chaise Sectional. 

More Examples…

Below, we see a brown LAF Chaise Sectional, determined by the fact that the chaise piece’s arm is on the left side when we are facing the sectional.

Second, we see a gray RAF Sofa Sectional, named this way because the sofa piece’s arm is on the right side when were are facing the sectional (the left side is an armless chair and a LAF loveseat).