Definition of fellow noun from the Oxford Advanced Learner's Dictionary
fellow
noun
ˈfeləʊ ˈfeloʊ
1(informal, becoming old-fashioned) a way of referring to a man or boyHe's a nice old fellow. see also fella2[usually plural]a person that you work with or that is like you; a thing that is similar to the one mentionedShe has a very good reputation among her fellows.Many caged birds live longer than their fellows in the wild.3(British English) a senior member of some colleges or universitiesa fellow of New College, Oxford4a member of an academic or professional organizationa fellow of the Royal College of Surgeons5(especially North American English) a graduate student who holds a fellowshipa graduate fellowa teaching fellow
ˈfeləʊ 
ˈfeloʊ 
1 (informal, becoming old-fashioned) a way of referring to a man or boyHe's a nice old fellow. see also fella2 [usually plural] a person that you work with or that is like you; a thing that is similar to the one mentionedShe has a very good reputation among her fellows.Many caged birds live longer than their fellows in the wild.3 (British English) a senior member of some colleges or universitiesa fellow of New College, Oxford4 a member of an academic or professional organizationa fellow of the Royal College of Surgeons5 (especially North American English) a graduate student who holds a fellowshipa graduate fellowa teaching fellow