Webster's Revised Unabridged Dictionary · 1913

Fellow

Fellow , noun

[Old English felawe, felaghe, Icelandic fēlagi, from fēlag companionship, prop., a laying together of property; property + lag a laying, pl. log law, akin to liggja to lie. See Fee, and Law, Lie to be low.]

1.
A companion; a comrade; an associate; a partner; a sharer.
The fellows of his crime. — Milton
We are fellows still, Serving alike in sorrow. — Shakespeare
That enormous engine was flanked by two fellows almost of equal magnitude. — Gibbon

Commonly used of men, but sometimes of women.

2.
A man without good breeding or worth; an ignoble or mean man.
Worth makes the man, and want of it, the fellow. — Pope
3.
An equal in power, rank, character, etc.
It is impossible that ever Rome Should breed thy fellow. — Shakespeare
4.
One of a pair, or of two things used together or suited to each other; a mate; the male.
When they be but heifers of one year,... they are let go to the fellow and breed. — Holland
This was my glove; here is the fellow of it. — Shakespeare
5.
A person; an individual.
She seemed to be a good sort of fellow. — Dickens
6.
In the English universities, a scholar who is appointed to a foundation called a fellowship, which gives a title to certain perquisites and privileges.
7.
In an American college or university, a member of the corporation which manages its business interests; also, a graduate appointed to a fellowship, who receives the income of the foundation.
8.
A member of a literary or scientific society; as, a Fellow of the Royal Society.
Were the great duke himself here, and would lift up My head to fellow pomp amongst his nobles. — Ford

Fellow is often used in compound words, or adjectively, signifying associate, companion, or sometimes equal. Usually, such compounds or phrases are self-explanatory; as, fellow-citizen, or fellow citizen; fellow-student, or fellow student; fellow-workman, or fellow workman; fellow-mortal, or fellow mortal; fellow-sufferer; bedfellow; playfellow; workfellow.

Fellow , transitive verb

To suit with; to pair with; to match. [Obsolete] — Shakespeare