1. A base metal is any metal other than the noble metals or precious metals (gold, silver, platinum, etc.)
2. base metal is the principal metallic element in an alloy. For example, the base metal of bronze is copper.
Helmenstine, Anne Marie, "What Is a Base Metal?
Definition and Examples." ThoughtCo, Jun. 13, 2018, thoughtco.com/base-metal-definition-and-examples-608464.
