noun anything which unites or cements.
2. solder ·noun to mend; to patch up.
3. solder ·noun a metal or metallic alloy used when melted for uniting adjacent metallic edges or surfaces; a metallic cement.
4. solder ·noun to unite (metallic surfaces or edges) by the intervention of a more fusible metal or metallic alloy applied when melted; to join by means of metallic cement.