is that a new rule of grammer that you made up yourself? When the Catholic Church was the ONLY Christian Church on Earth, for those 1,600 or so years, did she declare that she was the only denomination??, probably not. However when the revolution took place, there had to ba a way to "name" all the new groups and so they were nominated, that is, named....Lutheraans, Methodists, Calvinists, Baptists....see, they were named so you could tell the different ways that they were not Catholic.
Encyclopedias and Catholic serving publications and the rest of us all know the Catholic denomination as one of the Christian denominations.
What you or Mormons consider insider teachings for yourselves within your church doesn’t interest me and the people who don’t belong to your denomination, or in the case of Mormons, their religion.