The words in this set refer to professional, business, or work relationships between people. Associate is the least specific of these; its formality would suggest a business or professional context. While it implies close connection, the relationship might be the result of choice, chance or necessity; a man’s business associates . In a more specific use, associate is a component of some professional titles, denoting the second of three ranks: an associate editor; an associate professor. It is also used specifically to indicate less than full membership in a group; A member pays $40 annually in dues, but you can become an associate for $10. In this sense, associate may refer either to a person or to a group within a larger group. Affiliate compares with this use of associate in being now mostly used of a group related to another group: the television affiliate of a city newspaper. It is frequently used to relate a small group to a national or international parent group: the local affiliate of the Royal Life Saving Society. The word suggest that two affiliates are co-equal in a loose relationship of autonomous groups, even when a smaller-to-larger hierarchy is involved. This contrasts with associate in its suggestion of subordinate membership in a group.

Ally and partner may apply either to individuals or to groups. Ally always suggests a relationship of choice. One’s allies unite with one in a common cause and most often against a common enemy. Allies are not necessarily friends outside the cause that jointly concerns them: The two members were enemies on questions of domestic affairs, but allies on foreign policy. Ally is chiefly used in reference to nations that are on the same side in an international war: England and Russia were allies in World War II. Partner , like ally , may apply to one nation joined with another in a common cause: France and England were partners in an atomic power project. But partner often indicates a close or contractual relationship. It is the legal term for one of he co-owners of a business: He was made a partner in the firm. And it may also refer to a much more personal association: marriage partners . Unlike the other words in this group, partner sometimes points to a one-to-one relationship involving a couple or a pair: his dancing partner ; to draw for partners in playing bridge.

The remaining words refer exclusively to person-to-person relationships, as does associate in its more general sense. Co-worker is the least formal of these and applies as readily to manual labour as to more highly skilled occupations: his co-workers in the factory; his co-worker on the government’s conservation project. Co-worker is distinctly neutral in tone, implying neither animosity nor the cordiality that may be suggested by associate . Colleague is restricted almost solely in use to professional association . It is formal in tone, but may range in feeling from neutrality to an expression of respect or approbation: my colleagues in the philosophy department. Fellow , as here considered, is now seldom used except as a title or component. In an academic context, it may mean a graduate student on a fellowship grant, but it may also be used of certain faculty positions: a Fulbright fellow at Auckland University; a fellow of All Souls College, Oxford.