Meaning of base metal

base' met'al

Pronunciation: [key]
  1. any metal other than a precious or noble metal, as copper, lead, zinc, or tin. Cf. noble metal, precious metal.
  2. the principal metal of an alloy.
  3. the principal metal of a piece underlying a coating of another metal; core.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.