slag Meaning, Definition & Usage

  1. noun the scum formed by oxidation at the surface of molten metals
    dross; scoria.
  2. verb convert into slag

WordNet

Slag noun
Etymology
Sw. slagg, or LG. slacke, whence G. schlacke; originally, perhaps, the splinters struck off from the metal by hammering. See Slay, v. t.
Definitions
  1. The dross, or recrement, of a metal; also, vitrified cinders.
  2. The scoria of a volcano.

Webster 1913