A solder is a fusible metal alloy, with a melting point or melting range of 180-190°C (360-370 °F), which is melted to join metallic surfaces, especially in the fields of electronics and plumbing, in a process called soldering.
The word solder comes from the Middle English word soudur, via Old French soldure and soulder, from the Latin solidare, meaning '‘to make solid’'.