Where is the post in a crochet stitch?
Typically, crocheters work stitches through the top of the stitch. (AKA that little V on the top edge of the fabric where you insert your hook.) The bottom part of the stitch — that actually makes up the fabric — is called a post.
What does it mean to work around the post?
Instead of inserting the hook into the front and back loops of the stitch, when working post stitches, we work around the post.