A bolt is a form of threaded fastener with an external male thread. Bolts are very closely related . Further information: List of screw drives. Bolts use a wide.

A nut is a type of fastener with a threaded hole. Nuts are almost always used in conjunction with a mating bolt to fasten multiple parts together.

A screw is a type of fastener, in some ways similar to a bolt, typically made of metal, and characterized by a helical ridge, known as a male thread.

A washer is a thin plate (typically disk-shaped, but sometimes square) with a hole (typically in the middle) that is normally used to distribute the load of a threaded fastener, such as a bolt or nut.