Nut

The bolt consists of a head and a cylindrical body with screw threads along a portion of its length. The nut is the female member of the pair, having internal threads to match those of the bolt. Washers are often used to prevent loosening and crushing.
Nuts are fasteners with threaded holes that secure to bolts, screws or studs and hold parts together.
A nut is a type of fastener with a threaded hole. Nuts are usually used opposite of a bolt to fasten parts together. The nut and bolt are held together by their threads' friction, a slight stretch of the bolt, and compression of the parts.
Bolts are designed to be used with a nut, which creates a strong clamping force when tightened. This makes them ideal for applications that require high levels of stress and force, such as construction, manufacturing, and automotive.
The manufacturing, engineering, and construction and building industries are some of the industries that heavily make use of bolts and nuts. For putting together and securing different structures, items of machinery, and components of equipment, they are both necessary.