Well, it's not a well defined term, that's part of the problem. I think it's worth the effort to challenge the language used to describe class and power, though, because the terminology omits the existence of the elite. I've addressed that elsewhere in the thread so won't rehash it again here, but it has revealed to me some of the weird psychological barriers in place preventing the rehabilitation of the language we use. For one, the middle doesn't want admit to themselves how far they truly are from actual power and prefer to think of themselves as high or near-high. Second, the shear exponential scale of the power disparity between the middle and high is hard to comprehend.