The English name for a screw is "fastener", which is a general term and is also called a fastening part or a standard part. A bolt is called "bolt" in English and is basically used in places with pre-formed threads. A nut is called "nut" and is used in conjunction with a bolt, and the tool for working with it is usually a wrench.

The main classifications of screws include ordinary screws, self-tapping screws and expansion screws.

The head screw Capscrew was originally limited to full-threaded fasteners, but this is no longer the standard usage nowadays.

A machine screw, generally speaking, is a screw with a diameter less than ¼ inch (4# to 12#), usually with full threads and driven by a screwdriver, such as a Phillips head, a十字head or an internal hexagonal head, etc.

The hexagonal head screw (Hexcapscrew) and the large hexagonal bolt (Hexbolt) are, as their names suggest, external threaded fasteners with a hexagonal head. They are designed to be turned using a wrench. According to the ASME B18.2.1 standard, the head height and rod length tolerances of the hexagonal head screw (Hexcapscrew) are smaller than those of the ordinary large hexagonal bolt (Hexbolt). Therefore, ASME B18.2.1 hexagonal screws are suitable for installation in all places where large hexagonal bolts can be used, including those where the large hexagonal bolts are too large to be used.

The socket cap screw, also known as the socket head screw or the Allen bolt, is a type of screw with a hexagonal internal hole at its head. It can be tightened or loosened by inserting a hexagonal key (hex key, Allen wrench, or Allen key) into the internal hole. The most commonly used type of internal hexagonal screw is the cylindrical head screw, with the head diameter being approximately 1.5 times the main diameter of the thread (1960 series). Other head types include the semi-circular head screw (Bottom head capscrew) for aesthetic surface appearance and the countersunk head screw (Countersunk head capscrew) suitable for conical screw holes. The blind hole design allows the screw head to remain hidden from the surface of the object being fixed while still being able to rotate, making it widely used in areas with smaller surfaces where traditional screwdrivers are inconvenient to use.