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]
(..) - How long have you known Senator Smith? - A good many years. He used my land up around Willet Creek for his boy rangers. Seemed like a nice fellow. One day he said he had a great chance to sell that land for an acre. I'd be glad to get for it. So we set it up like this: I deeded him the land and (..)1939 Mr. Smith Goes to Washington
(..) And to Don Quixote. - Do you know how I felt? - How did you feel? Quick! I felt just like a mother sending the kid off to school for the first time. Watching her little fellow toddling off in his best bib and tucker. Hoping he can stand up to the other kids. Say, who started this? (..)1939 Mr. Smith Goes to Washington