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]
(..) - Are those sirens? - No. - Peter, No!, Peter! - No sirens. Peter, Peter! Good morning, esteemed faculty and families of my fellow graduates. It's an honor to be standing up here today. Hello...I told you, I'm running a bit late. I saw that, Spider. I know that we all think we're immortal. (..)2014 The Amazing Spider-Man 2