Solder is a metal alloy used to join two or more electronic components together. It typically consists of a mixture of tin and lead, although lead-free alternatives are also available. When heated, solder melts and flows into the joint, creating a strong electrical and mechanical connection once it cools and solidifies. Soldering is a common technique in electronics, used in the assembly of circuit boards and other devices. The process requires a soldering iron to heat the solder, allowing it to bond with the surfaces of the components being joined. Proper soldering ensures reliable performance in electronic applications.