What is the difference between bolts, screws and studs?

"Screws" are just a general term for fasteners. They are everyday words. They include: bolts, screws, nuts. As long as there are threaded fasteners, screws, nuts, bolts, and screws all have something in common, that is, they have threads. In addition to the thread, what is the difference? The following small series introduces the difference between bolts, screws and studs? How to distinguish the screw fasteners? Let's understand it!