Solder \Sol"der\, n. [Formerly soder; F. soudure, OF. soudeure, fr. OF. & F. souder to solder, L. solidare to fasten, to make solid. See Solid, and cf. Sawder.]

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.

Source: Webster's Revised Unabridged Dictionary (1913)
 

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.

2. To mend; to patch up. ``To solder up a broken cause.'' --Hooker.

Source: Webster's Revised Unabridged Dictionary (1913)