I suspect that we might not use the term “dwarf planet”, were it not that the objects we initially created the category to describe were originally classed as planets. The category labelling is a bit arbitrary, we just discovered that what we now call dwarf planets are quite abundant and that there was a clear line that could be drawn to distinguish them from the rest of what we called planets, and so decided to draw that line between them.
I suspect that we might not use the term “dwarf planet”, were it not that the objects we initially created the category to describe were originally classed as planets. The category labelling is a bit arbitrary, we just discovered that what we now call dwarf planets are quite abundant and that there was a clear line that could be drawn to distinguish them from the rest of what we called planets, and so decided to draw that line between them.