Yeah that has always seemed a bit jumbled to me. It's not clear to me why that point, 33,500 feet below the peak of Mauna Kea, is appropriate to use as a basis

Yeah that has always seemed a bit jumbled to me. It's not clear to me why that point, 33,500 feet below the peak of Mauna Kea, is appropriate to use as a basis of measurement for the mountain. And why not a lower point? And why can that point not be used to measure the height of Mount Everest as well? Anyway, I think what you're asking can usually be described by the concept of Topographic Prominence[1], one definition of which is "the height of the peak’s summit above the lowest contour line encircling it but containing no higher summit" [1] https://en.wikipedia.org/wiki/Topographic_prominence https://en.wikipedia.org/wiki/Topographic_prominence