Self-locking nut, locknut, locking nut, four-claw nut, driving nut safety nut, thin rod screw connecting nut self-locking hexagonal cap nut special anchor screw nut, hexagonal crown thin nut suspension ring nut.
As the name suggests, it generally refers to the screws used on mechanical equipment. It is generally the metric system and the British system, the American system, the Japanese standard...