What Is The Proper Name For This Placard

I’ve always been confused about the GVRW specs. The front and rear added together seems to equal the total, so that makes sense. But what does GVRW stand for? Presumably the GVW part means “gross vehicle weight”. But then what does the “R” mean? I presume it mean “road”. So if GVRW is the maximum road weight, how does the owner figure out how much stuff can be put into the vehicle before exceeding that weight? They’d need to know the vehicle’s weight with everything removed, but that’s not provided on the label. .