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]
(..) Thus ... Our relationship ... Relationship? Very well.. partnership Has not yet run it's course, My dear fellow if you could be bothered to see this through to the end, I shall never again ask you to assist me. Once more... Onto the bridge That's the spirit! Now... To the question, (..)2011 Sherlock Holmes: A Game of Shadows