What does brethren mean?
"Brethren" is a formal, literary, or archaic plural of the noun "brother," used today almost exclusively to refer to fellow members of a religious community, monastic order, profession, or fraternal organization. Where "brothers" serves as the ordinary plural in everyday speech — whether describing family relations or close friends — "brethren" survives in solemn and institutional registers: an abbot may address his brethren at prayer, a lawyer may speak of his brethren at the bar, and a minister may open a sermon with "dear brethren." Capitalized as "the Brethren," it also names certain Protestant Christian groups, notably the Plymouth Brethren. The word descends from Old English "brōþor" through a Middle English plural formed by analogy, and it shares a deep Indo-European root with Latin "frater" and Greek "phratēr," which gave English such words as "fraternal" and "fraternity." Its connotations are communal, reverent, and slightly antiquated, which makes it useful precisely when ordinary language feels too casual.
nounAn archaic or formal plural of "brother," used chiefly to refer to fellow members of a religious community, profession, or organization. It carries a solemn, traditional, or institutional tone.
- A formal, literary, or archaic plural of "brother," especially referring to fellow members of a religious community, monastic order, profession, or fraternal organization.
- (Capitalized as "the Brethren") Members of specific Christian groups, such as the Plymouth Brethren or other Brethren denominations.
"The abbot addressed the assembled brethren at morning prayers."
"The prior reminded his brethren that silence was to be observed after compline."
"In his farewell speech, the retiring judge thanked his brethren at the bar for their support."
As a noun, "brethren" functions as a plural; the regular modern plural "brothers" is preferred outside formal, religious, or literary contexts.
"The brethren gathered in the chapter house to elect a new prior."
"Brethren" isn't just old-fashioned "brothers" — it's the plural English kept alive almost exclusively for monks, clergy, and tight-knit communities, making it one of the few plurals with its own job description.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of brethren
Brethren originated as a double plural of Old English "brōþor": Middle English speakers formed "brether" by changing the root vowel (as in "men" from "man") and then added the plural ending "-en" (as in "children"), yielding "bretheren." The word traces back through Proto-Germanic *brōþēr to the Proto-Indo-European root *bʰreh₂ter-, meaning a male of the same parents or, by extension, a fellow member of a group. This ancient root also produced Latin "frater" and Greek "phratēr," making "brethren" a distant cousin of "fraternal," "fraternity," and "friar." By the early modern period, "brothers" had displaced "brethren" in general use, leaving it chiefly in religious, legal, and fraternal contexts.
Related word forms
How brethren is actually used
Register is formal, literary, or ecclesiastical; using "brethren" for ordinary siblings would sound quaint or affected today. In everyday modern English, "brothers" has replaced it entirely except in fixed religious and ceremonial contexts.
Easily confused with brethren
"Brothers" is the standard modern plural of brother used in everyday contexts, while "brethren" is a literary or archaic plural reserved mainly for members of religious orders, professions, or close-knit communities.