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]
(..) When I walked in, I knew I was right. Did you feel that way? I wouldn't be here if I didn't. - Where are you from? - Upstate. That fellow you work with, I don't like him. Not that I don't like him. I just think he's silly. I don't think he respects you. I don't believe I've ever met anyone (..)1976 Taxi Driver
(..) Yeah, I have. - You carry a piece? - No. - You need one? - No. If you ever need one, I know a fellow who can get you a real nice deal. Lots of shit around. I never use mine. I'm conservative. But it's a good thing to have just as a threat. I'm gonna go do my dirt. (..)1976 Taxi Driver