What kind of bolt is called a carriage bolt?

Generally speaking, a bolt is used to connect two objects, usually through a light hole, and needs to be used in conjunction with a nut. A single bolt cannot connect. A wrench is generally used as a tool. The heads are mostly hexagonal heads, etc., generally larger. The carriage bolt is applied in the groove, and the square neck is stuck in the groove during installation, which can prevent the bolt from rotating, and the carriage bolt can move in parallel in the groove. Since the heads of the carriage bolts are round, there is no design of useful power tools such as cross grooves or hexagon sockets, and they can also play a role in preventing theft in the actual connection process.