The definition of white is that same as that for any other racial group: a member of the white racial group, determined by a combination of lineage, how one is

The definition of white is that same as that for any other racial group: a member of the white racial group, determined by a combination of lineage, how one is perceived, how one perceives themselves, and more. It can be complicated, and so is usually just determined by a “I know it when I see it” test, or self identification. But certain hard rules like where your ancestry is from and how your parents race is exist. Not only is it racist, there’s also no sense in tying extra garbage like “level of discrimination” to the definition of white - it just doesn’t match up to observed reality. White people have been enslaved, white people are discriminated against in many countries where they aren’t the majority, white groups receive varying levels of discrimination even now. These facts don’t make a person any more or less white.