1 Any combination or compound of metals fused together; a mixture of metals; for example, brass, which is an alloy of copper and zinc. But when mercury is one of the metals, the compound is called an amalgam.
2 The quality, or comparative purity, of gold or silver; fineness.
3 A baser metal mixed with a finer. Fine silver is silver without the mixture of any baser metal. Alloy is baser metal mixed with it. Locke.
4 Admixture of anything which lessens the value or detracts from; as, no happiness is without alloy. “Pure English without Latin alloy.” F. Harrison.

1 To reduce the purity of by mixing with a less valuable substance; as, to alloy gold with silver or copper, or silver with copper.
2 To mix, as metals, so as to form a compound.
3 To abate, impair, or debase by mixture; to allay; as, to alloy pleasure with misfortunes.