Shell is a crochet stitch, a special kind of needlework done by interlocking looped stitches with a hooked needle. A shell is simply a group of stitches which are placed in a single stitch or space. They are usually double crochet, but could be another stitch The alternating shells and single crochets make this a fast and easy stitch pattern to do.

These stitches forms the thread around the edge of the fabric in a shell appearing configuration. To make shell stitch, one hook is used to form a chain of stitches from which variations of designs can be created. The chain stitch is used to cast loops onto the hook and create pattern spaces. Shell stitch made with single crochet creates solid-pattern designs and bars in an open-work pattern. Those made with double crochet is used in the same manner as single crochet, but is twice the width.