Brother: A Male Sibling, and a Word Borrowed by Everyone
A brother is a male sibling. The word has been lent to monks, unions, churches and friends, which is why it has two different plurals.
Brother names a male sibling first and a great deal else afterwards. Religious orders, trade unions and congregations all use it for members. It is one of the very few English nouns with two live plurals: brothers for family, brethren for the rest.
- A male sibling. *My older brother lives abroad.*
- A member of a religious order. *Brother Thomas ran the garden.*
- A fellow member of a group. *Brothers in the union.*
- A close friend (informal). *Thanks, brother.*
Word forms
| Form | Word | Example |
|---|---|---|
| Noun | brother | Her younger brother. |
| Plural | brothers | Three brothers. |
| Plural (formal) | brethren | Dearly beloved brethren. |
| Adjective | brotherly | Brotherly advice. |
| Noun | brotherhood | A sense of brotherhood. |
How it is used in a sentence
- My brother-in-law is a teacher.Plural is brothers-in-law, not brother-in-laws.
- They were like brothers.Comparison, not literal family.
- The brethren gathered in the chapel.Religious or fraternal, never for actual siblings today.
Family words with the same root
- German *Bruder*, Dutch *broeder*, Swedish *bror*
- Latin *frater*, giving English fraternal and fraternity
- Sanskrit *bhratar*
- It is one of the most stable words in the Indo-European family, barely changed in thousands of years
From Old English *brothor*. That stability is not an accident: kinship terms are learned in infancy and used constantly, so they resist the sound changes that reshape other vocabulary.
Brothers or brethren?
Brothers for family. Brethren survives only in religious, legal and fraternal language, where it sounds deliberately formal.
What is a half-brother?
A brother who shares one parent. A stepbrother shares no parent but is connected through a parent's remarriage.