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]
(..) I'll do the taking today. You sold your soul to Satan, Your Grace. You accused innocent men of witchcraft and let them die. Brother Friar, you would not strike a fellow man of the cloth. No, I wouldn't. I'll help you pack for your journey. You'll need lots of gold. You're a very rich man. This too. (..)1991 Robin Hood: Prince of Thieves