Yarn over (YO) is a fundamental knitting technique that involves wrapping the yarn around the right-hand needle before knitting the next stitch. This action creates a small loop of yarn on the needle, which is then used to create a variety of patterns and textures in the fabric.
Yarn overs are commonly used in lace knitting, where they create openwork and delicate patterns. They can also be used to create cables, bobbles, and other decorative elements. Additionally, yarn overs are essential for shaping garments, as they can be used to increase or decrease stitches.