brother

American  

[bruhth-er, bruhth-ur] / ˈbrʌð ər, ˈbrʌðˈɜr /

noun

plural

brothers,

plural

brethren

1. a male offspring having both parents in common with another offspring; a male sibling.

2. Also called half brother.  a male offspring having only one parent in common with another offspring.

3. a stepbrother.

4. a male numbered among the same kinship group, nationality, ethnicity, profession, etc., as another; an associate; a fellow member, fellow countryman, fellow man, etc..

   a fraternity brother.

5. Ecclesiastical.

   1. (often initial capital letter) a male numbered among the lay members of a religious organization that has a priesthood.

   2. a man who devotes himself to the duties of a religious order without taking holy orders, or while preparing for holy orders.

6. brothers, all members of a particular racial or ethnic group, or of the human race in general.

   All men are brothers.

7. Slang. fellow; buddy.

   Brother, can you spare a dime?

8. Informal. a term used to refer to or address a fellow Black man; soul brother.

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interjection

1. Slang. (used to express disappointment, disgust, or surprise.)

brother British  

/ ˈbrʌðə /

noun

1. a male person having the same parents as another person

2. short for half-brother stepbrother

3. 1. a male person belonging to the same group, profession, nationality, trade union, etc, as another or others; fellow member

   2. ( as modifier )

      brother workers

4. comrade; friend: used as a form of address

5. Christianity

   1. a member of a male religious order who undertakes work for the order without actually being in holy orders

   2. a lay member of a male religious order

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interjection

1. slang an exclamation of amazement, disgust, surprise, disappointment, etc

Related Words

Brothers, brethren are plurals of brother. Brothers are kinsmen, sons of the same parents: My mother lives with my brothers. Brethren, now archaic in the foregoing sense, is used of male members of a congregation or of a fraternal organization: The brethren will meet at the church.

Other Word Forms

• brotherless adjective
• brotherlike adjective

Etymology

Origin of brother

First recorded before 1000; Middle English; Old English brōthor; cognate with Dutch broeder, German Bruder, Old Norse brōthir, Gothic brothar, Sanskrit bhrātṛ, Greek phrā́tēr, Latin frāter, Old Irish bráthair, Old Church Slavonic bratrŭ

Example Sentences

Brian works for a biotech company in California and learned only recently that his brother had nothing in a 529.

From The Wall Street Journal • Mar. 31, 2026

Because he’s under 18, his older brother is listed on paperwork running the organization.

From Los Angeles Times • Mar. 31, 2026

The California lawmaker also noted that members of Congress have sought testimony from the King's brother, Andrew Mountbatten-Windsor, as well as Peter Mandelson, the UK's former ambassador to the US, about their ties to Epstein.

From BBC • Mar. 30, 2026

The King said last month that the Royal Family were "ready to support" police in their inquiries after his brother was arrested and then released on suspicion of misconduct in public office.

From BBC • Mar. 30, 2026

Was Katherine supposed to have a brother at all?

From "Found" by Margaret Peterson Haddix

Related Words

• relative
• twin