Is it copyright if a business has the name I want to use in my fantasy novel?

Not entirely sure but if the name is derived from something else that was in the public domain they really wouldn't have a leg to stand on if they did try to sue. Like say if I name a race of creatures Scions the car company really couldn't claim copyright infringement because a scion is part of a plant that is grafted onto another plant. I'm not sure what the company is or where it derives its name from so I can't be sure if it would be copyright infringement or not, if the name is randomly made up by you and it just so happens to be the same name as an existing company that may hit a little too close to home. Try changing the spelling in that case. Of course there are probably others out there with a little more knowledge on this subject than me. It might even be that if the character or race was completely unrelated to the company it shares a name with that use of the name would fall under fair use. But I can't say for certain. Also look up the origin of the company name, if the name is taken from a family surname then it might fall into public domain anyway. Copyright law is very confusing.