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]
(..) never been attacked by the Vikings? What do you mean, sire? Neither your lands... nor the lands of your fellow conspirators... have ever suffered any real harm. For years, you have schemed against me! I'll not be made a scapegoat... (..)1958 The Vikings