Where did the phrase milling around originate?

The phrase "milling around" originated from the practice of milling, which is the process of grinding or crushing grains into flour. In this context, "milling around" refers to a group of people moving around in a disorganized or aimless manner, similar to the way grains move around in a milling machine. The term has since evolved to describe a crowd or group of people moving about without a clear purpose or direction.