P2Tog (Purl Two Together): Just the opposite of the K2Tog, this stitch is most often done on the purl (or wrong) side of your work.
What does P2Tog mean?
P2tog (purl two stitches together) is a simple decrease used for shaping in knitting patterns. The technique and steps are exactly the same as when purling, except that you work into two stitches at the same time.
What is p2tbl?
p2tbl means purl two together through the back loop.