Colleague comes from Latin 'collēga' (one chosen together), originally describing Roman magistrates who shared an office.
A person with whom one works in a profession or business; an associate in professional or official duties.
From French collègue, from Latin collēga (one chosen along with another, a partner in office), from com- (together, with) + legere (to choose, to gather, to appoint). In Roman political life collēga specifically meant a fellow magistrate — the two consuls were each other's colleagues, bound by mutual veto power (the intercessio). The verb legere (to gather, to choose) is from PIE