Somebody who belongs to a different ethnic or "racial" background to the majority (or just largest group) in a country/city/town etc. Initially Italians, Poles, Irish and so on were considered minorities in the US until they assimilated into the "white" majority.
Contrary to the other definition, the "Caucasian gene" is only recessive because of the racist "
one drop rule". For example, the likes of
Rashida Jones and
Colin Powell have a skin tone that is arguably closer to "white" than "black".