In this article I read that:
Fellow – Avoid using "fellow" when you mean "a person." Calling someone a fellow is more formal than calling him or her a dude, but "fellow" is still a colloquialism.
This question ensures that "fellow student" is correct, but I need to know whether it is formal usage or not.
I am writing a formal application and want to refer to a fellow university student.
Should I use "fellow student" or do I have a better choice?