Sol·der n.  A metal or metallic alloy used when melted for uniting adjacent metallic edges or surfaces; a metallic cement. Hence, anything which unites or cements.
 Hard solder, a solder which fuses only at a red heat, as one composed of zinc and copper, or silver and copper, etc.
 Soft solder, a solder fusible at comparatively low temperatures; as, plumbers' solder, consisting of two parts lead and one part tin, is a soft solder.
 soft solder
      n : solder that melts at a relatively low temperature