Welding is a fabrication process that joins materials, typically metals or thermoplastics, by using heat, pressure, or both. This creates a strong bond between the materials being joined, resulting in a seamless, long-lasting connection. There are several types of welding processes, including arc welding, gas welding, and resistance welding, each with its own specific technique and equipment requirements. Welding is commonly used in various industries such as construction, automotive, aerospace, and manufacturing to assemble or repair structures and products.