- The scum or refuse matter which is thrown off, or falls
from, metals in smelting the ore, or in the process of melting;
recrement. - Rust of metals. - Waste matter; any worthless matter separated from the better
part; leavings; dregs; refuse.
Meaning of 'dross' (Princeton's WordNet)
1 . dross
[ n]
Meaning (1): - worthless or dangerous material that should be removed