Blackness/Whiteness is an interesting concept - it’s remarkably fluid, especially with changes in time and place. Race isn’t the same as ethnicity or genetics, or a direct result of it, although racists often try to claim it is - a stark example of this in Western societies like the US and Australia would be how they categorize Italian and Greek peoples, Slavic peoples, or ethnically-Jewish peoples - the idea of whether or not each of these is White has largely shifted over time, often as a group stops being the current biggest immigration demographic. The USA even had a concept of “Black Irish”, which originally meant a post-Famine Irish refugee. Human races are ultimately just social classes, not a biological concept.
Another aspect, related to this thread, is hypodescent. In some societies (it’s not a universal thing!), if a child has a Black parent and a White parent, is the child Black or White, or another label entirely? As mentioned in that article, some US states used to legally define someone as Black even if only 1 of their 16 great-great-grandparents were Black.



Linking to a reply I posted in this thread because it talks about a relevant aspect, which other (correct) comments haven’t named: hypodescent.
https://lemmy.ml/post/47987898/25930253