Knitting requires a steady focus - concentration. You have to keep track of where you are, so you have to stay in the moment. When you are good enough that you do not have to think through every step, you can just watch yourself do the knitting. Maybe it wouldn't be meditation if you did it in a group and everyone was talking, but on your own it has all the qualities of traditional meditation. The only thing missing is the name. You probably already find that it makes you feel calmer, more in control, and more peaceful.