[1] : The Collaborative International Dictionary of English v.0.48

slag \slag\ sla^g, n. sw. slagg, or lg. slacke, whence g.
   schlacke; originally, perhaps, the splinters struck off from
   the metal by hammering. see slay, v. t.
   1. the dross, or recrement, of a metal; also, vitrified
      cinders.
      1913 webster

   2. the scoria of a volcano.
      1913 webster

   3. metal. a product of smelting, containing, mostly as
      silicates, the substances not sought to be produced as
      matte or metal, and having a lower specific gravity than
      the latter; -- called also, esp. in iron smelting,
      cinder. the slag of iron blast furnaces is essentially
      silicate of calcium, magnesium, and aluminium; that of
      lead and copper smelting furnaces contains iron.
      webster 1913 suppl.

   slag furnace, or slag hearth metal., a furnace, or
      hearth, for extracting lead from slags or poor ore.

   slag wool, mineral wool. see under mineral.
      1913 webster
see also:
slay cinder slag furnace slag hearth slag wool mineral 

Slag >> S Words
Slag, definition of term: Slag
slag_pag1.html

Furnace >> F Words
Furnace, definition of term: Furnace
furnace_pag1.html

Blast Furnace >> B Words
Blast Furnace, definition of term: Blast Furnace
blast+furnace_pag1.html