It’s better than that. There isn’t a single definition for white. Perhaps someone has one.

The best I can do, having studied Color Science at RIT, is that white is any spectral power distribution a person identifies as white. Yes, it’s a circular definition.

The topic is deeper than it might seem. I can put someone in a room and show them a color they would swear to be white. And then, in an instant, I can change that color by changing the surround, what you see peripherally. It’s freaky.