A person who shares with another specified person in a particular possession, office, undertaking, etc.; a partner, colleague, collaborator. Also…

a fellow labourer.

= workmate n.

A person linked to or associated with another, esp. in some work or activity; an associate or partner in an undertaking; a fellow-worker. Also…

(a) a person who works towards the same goal, in the same organization, or at the same occupation as another specified person; a collaborator, a…

A person or thing closely linked or associated with another in some way, as a spouse, a workmate, etc.; cf. yokefellow, n. Also occasionally literal…

Brother in the same craft or occupation; = French confrère.

a person with whom one works; a colleague.

A companion, workmate, or friend. Also as a form of address.

a close associate, colleague, or companion; (originally) spec. a police officer's partner.

A person who sits next to another at school (now chiefly East African). Also: a person who shares a desk with another at work.

Fellow-labourer.

dialect and slang. A fellow-workman, mate, or ‘chum’. Cf. Bob, n.7

a fellow-worker, co-worker.