The Collaborative International Dictionary of English v.0.48:

Solder \Sol"der\, v. t. [imp. & p. p. Soldered; p. pr. & vb.
   n. Soldering.] [Formerlysoder. See Solder, n.]
   1. 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.
      [1913 Webster]

   2. To mend; to patch up. "To solder up a broken cause."
      --Hooker.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Soldering \Sol"der*ing\,
   a. & n. from Solder, v. t.
   [1913 Webster]

   Soldering iron, Soldering tool, an instrument for
      soldering, consisting of a bit or bolt of copper having a
      pointed or wedge-shaped end, and furnished with a handle.
      [1913 Webster]

WordNet (r) 3.0 (2006):

soldering
    n 1: fastening firmly together [syn: bonding, soldering]