A hot melt glue gun is a handheld tool that melts solid plastic-like glue sticks to create a strong, fast-bonding adhesive. It uses a heating element to melt the glue, and a trigger mechanism pushes the molten adhesive out through a nozzle. The glue cools and solidifies quickly, making it ideal for crafts, DIY projects, and many industrial applications involving materials like wood, plastic, and fabric.