A bolt is a type of fastener used to securely join two or more objects, typically by inserting it through aligned holes and tightening it with a nut. Bolts usually have a threaded shaft and a head (hex, square, or other shapes) that allows for tightening with a tool such as a wrench. Made from materials like steel, stainless steel, brass, or titanium, bolts are used in construction, automotive, machinery, and industrial applications. They come in various types, including hex bolts, carriage bolts, anchor bolts, and eye bolts, each designed for specific strength and structural requirements.