I know nothing about scientific nomenclature, but I'm pretty confident that whether or not the Earth is round or if the Earth revolves around the sun is not a theory in any sense of the word.
Theory in the scientific definition is a lot different than theory in the popular definition. The earth being round is in fact a scientific theory -- it is backed up by tons of peer reviewed scientific research, making it a scientific theory.
https://en.m.wikipedia.org/wiki/Scientific_theory