As I said, the Arabs were by themselves who used the word "Copts" to refer to the native Egyptians who were the direct descendants of the Ancient Egyptians.
So the word used first to refer to Egyptians whose ancestors embraced Christianity in the first centuries after Christ. But since some of them were converted to Islam therefore the word was refer to all native Egyptian. But by the time it has undergone a semantic shift over the centuries to mean more specifically Egyptian Christian. This semantic shift dates back to the time when Christians became an Egyptian minority.
The other citizen in Egypt, the Muslims gave up that characteristic either because they were not ancestors of ancient Egyptian or because they were but converted to Islam and mixed with other strangers who came from the Arabia, Persia, Iraq, Turkey, Albania [ as was the last royal family] or from Caucas [Mamelukes who came as slaves].
It is very highly likely that Christian Egyptian was from Egyptian (the copts) that not converted to Islam and Survived by paying tax. They kept their Christianity, using the Coptic Calendar, remember their history,arts and myertrs. They continued to use the Coptic language against the odd till the last centuries.
So nowaday Copts is used for Christian Egyptians who use "Coptic Language", "Coptic Calendar", "Coptic Niroz" . These are not indicated Egyptian language , "Egyptian calendar" or "Egyptian New Year"
There is coptic Curches but never we named any Islamic mosque or islamic organisation to be Coptic Mosque or Coptic islamic institute,....
There is Coptic museum beside, Egyptian and Islamic museum shows items collected from Churches and people before the conquest of the Arabs.
Search any directionary or enclospidia about coptic and copts.
Watch any one from governement or pariament, journalists or tv broadcasting and notice when they refere to the christian Egyptian as the Copts and they speak about Coptic problem that not mean Egyptian problems. When told about Coptic Feast.
Notice the human right organisation talking about the copts's rights they don't mean Egyptian right.
Watch the all presidents when talking about the unity of the nations branches: muslims and copts.
Watch all the colums in neswpaper and headlines speak about the coptic community.
If we all Copts then:
- Why we don't use Coptic Language as our national language?
- Why nothing in history lessons in school about history of christianity in Egypt, and patariarches?
- Why nothing be told except in Churches about the Coptic Myrters.?
- Why we don't use Coptic Calendar?
- Why no Islamic organization uses "coptic" in its activities?
- Why no coptic division in faculties of art in the universities.
