I understand a civil war to be a struggle among internal groups for control of the government.
What is commonly referred to as our civil war was actually a war between 2 separate countries, the USA and the CSA.
It was more similar to our revolutionary war of the late 1700s.
This is my opinion. I may be wrong.
The official name used by the war department was the war of the rebellion. This I believe is most accurate. The United States had an election according to the constitution. There was no accusations of fraud or tampering in this election. Some southern states did not like the outcome of the election and decided to rebel by breaking away and forming their own country. So the democrats of 1860 said “not my president” just like the democrats of today like to do.