A crochet hook is a tool used in the craft of crochet, which involves creating fabric from yarn. It typically has a long, slender shaft with a hook at one end, allowing the user to pull yarn through loops to form stitches. Crochet hooks come in various sizes and materials, including metal, plastic, and wood, catering to different yarn types and project needs. Crochet hooks are essential for making a wide range of items, such as blankets, clothing, and accessories. The size of the hook affects the tightness and appearance of the stitches, making it important to choose the right one for each project.