dross (DRAWS, DROS) - n., (metallurgy) a scum of impurities on the surface of molten metal; waste matter, refuse; worthless, commonplace, or trivial matter.
Senses are given in chronological order, rather than order of importance -- the second is the most common, but the metaphoric extension that's third is also used. This one goes back, in the metallurgic sense, to Old English drōs, which in its Germanic roots turns out to be cognate with dregs. (BTW, the reason wrought iron gets worked (literally: wrought is an old past participle of work) is that, because it isn't heated enough to be liquid, the best way to get out what would (if melted) be dross is to bang on it.)
---L.
Senses are given in chronological order, rather than order of importance -- the second is the most common, but the metaphoric extension that's third is also used. This one goes back, in the metallurgic sense, to Old English drōs, which in its Germanic roots turns out to be cognate with dregs. (BTW, the reason wrought iron gets worked (literally: wrought is an old past participle of work) is that, because it isn't heated enough to be liquid, the best way to get out what would (if melted) be dross is to bang on it.)
---L.