Races, as descriptive terms, are nearly useless. But, "white" is by far the most meaningless, loaded term among them and we, as a society, need to do away with it entirely.
Ok, let me back up a bit.
What may surprise most people is that the concept of "race", as we know it today, didn't exist until around the 1680s as a way for European Americans to distinguish themselves from natives and the now racially specific slaves. So, yes, the foundation of "white" largely came out of racism... but, obviously, racism existed long before this. The different European nations all hated each other, the different Native American nations all hated each other, the Romans hated anyone who wasn't Roman, as did the Greeks, the Persians, and just about every nation before... for as long as there has been small tribes of humans wandering around, those different tribes hated each other. The difference was that this was based on ethnicity, referring to specific places of origin or culture. What made the new concept of "white" unique was that it suggested that the varied European ethnicities were close enough to each other that they could be grouped into one larger "race", as could other ethnicities into other broad races.
So, what does the term "white" literally mean? Anyone of European, Middle Eastern, or North African decent. That's how the term was defined in the 1600s, and that's how the US Census still defines the term today.
Now, of course you're thinking "Wait, Middle Easterners and North Africans are white? And doesn't that make Hispanics white too?"
Yes, it does. And, it's in the discrepancy between the word's definition and the word's usage that we can begin the analyze the true meaning "white".