Brethren, a term commonly used to refer to members of a religious or fraternal organization, has various synonyms. A few of them are enlisted here - brothers, comrades, colleagues, peers. The word brothers can be written as siblings, kin, or bros in informal settings. Comrades refer to individuals who are working towards a common goal. Colleagues signify people working in the same profession or organization. Peers are individuals who belong to the same age group or social status. Other synonyms for brethren include allies, associates, clansmen, and confederates. Each of these words has subtle differences in their meanings, but all are interchangeable synonyms for brethren.