Source : Webster's Revised Unabridged Dictionary (1913)

Welder \Weld"er\, n.
   One who welds, or unites pieces of iron, etc., by welding.

Welder \Weld"er\, n.
   1. One who welds, or wields. [Obs.]

   2. A manager; an actual occupant. [Ireland. Obs.] ``The
      welder . . . who . . . lives miserably.'' --Swift.

Source : WordNet®

welder
     n : joins pieces of metal by welding them together