The American Civil War was arguably not actually a civil war, but a war of secession.
I’m curious about this, because by definition, the American Civil War was a “civil war” (emphasis mine):
A civil war is a war between organized groups within the same state (or country). The aim of one side may be to take control of the country or a region, to achieve independence for a region, or to change government policies.
Those who don’t like calling it a “civil war” believe that the Confederacy actually became a legitimate separate country during that time, therefore it doesn’t count. It’s a mainly academic argument, until you realize that the reason they persist in calling it something else is that they think it’s still a separate country and that the Union is an illegal and illegitimate occupation force.
You can, of course, imagine the other stuff they also believe.
It is arguably about northern aggression since arguing anything is possible. That doesn’t make it correct.
It was a civil war because the states that declared they were seceding never successfully seceded. Otherwise there would have been a step where they rejoined the union, which wasn’t necessary because they were still member states of the US. That makes it a civil war.
40 years ago when I studied this war in school, the name was in fact, Secession War.
That may be dependent on where you went to school:
War of Separation/Secession
“War of Separation” was occasionally used by people in the Confederacy during the war. In most Romance languages, the words used to refer to the war translate literally to “War of Secession” […], a name that is also used in Central and Eastern Europe: Sezessionskrieg is commonly used in German language, and Wojna secesyjna is used in Polish. (Walt Whitman calls it the “War of Secession” or the “Secession War” in his prose).