alloy

Short definition from Wiktionary

Noun

1. 1
   A metal that is a combination of two or more elements, at least one of which is a metal, a base metal.
2. 2
   A metal of lesser value, mixed with a metal of greater value.
3. 3
   An admixture; something added which stains, taints etc.
4. 4
   Fusion, marriage, combination.

Verb

1. 1
   To mix or combine; often used of metals.
2. 2
   To reduce the purity of by mixing with a less valuable substance.
3. 3
   To impair or debase by mixture.