a teaching/research 'fellow' [=a graduate student who gets money in exchange for teaching/research]
He attended the concert with a 'fellow' student. [=someone who is a student, as he is]
He has always tried to be of service to 'his fellow man'. [=to other people]
(..) Merlin's beard! Is that an actual Acromantula? A dead one, I think, sir. Good God. Dear fellow, however did you manage to kill it? "Kill it"? My oldest friend, he was. I'm so sorry, (..)2009 Harry Potter and the Half-Blood Prince