I've never really thought about it before, but I'm not sure if "The Sun" actually has an officially sanctioned name! I'll accept "Sol", and "The Sol System". I'll also accept "Helios/The Helios System", or the "Terran System" to refer to our entire Solar System. And I'm sure many different cultures have their own term. But in terms of science/academia, I'm not sure that it has an official name. Looks like the IAU (International Astronomical Union) hasn't given it a sanctioned designation. [0] [1] [2]