A fastener is a hardware device used to join two or more objects together. Common types of fasteners include screws, bolts, nuts, and rivets. They are essential in construction, manufacturing, and everyday items, providing stability and strength to various structures and products. Fasteners come in various materials, such as metal, plastic, and wood, and are designed for specific applications. For example, screws are often used in woodworking, while bolts are typically used in heavy machinery. Proper selection and installation of fasteners are crucial for ensuring safety and durability in any project.