Brother vs. Brethren — What's the Difference?

A brother is a man or boy who shares one or more parents with another. The female counterpart is a sister.

(figuratively) The body of members, especially of a fraternal, religious or military order.

A male having the same parents as another or one parent in common with another.

(plural) the lay members of a male religious order

A kinsman.

A plural of brother.

A fellow man.

Brethren Any of various Protestant denominations, especially those arising out of the Anabaptist and Pietist movements in Central Europe between the 15th and 18th centuries.

A fellow member, as of a fraternity, trade union, or panel of judges on a court.

(archaic) brother

A close male friend; a comrade.

(poetic) kinsmen

A fellow African American man or boy.

Of or akin to; related; like

Pl. also brethren Something, such as a corporation or institution, that is regarded as a member of a class

Abbr. Br. or Bro. A lay member of a religious order of men.

Pl. also brethren A fellow member of the Christian church.

Son of the same parents as another person.

A male having at least one parent in common with another (see half-brother, stepbrother).

A male fellow member of a religious community, church, trades union etc.

(informal) A form of address to a man.

(AAVE) A black male.

Somebody, usually male, connected by a common cause, situation, or affection.

Someone who is a peer, whether male or female.

(poetic) Someone who is a kinsman or shares the same patriarch.

(transitive) To treat as a brother.

Expressing exasperation.

A male person who has the same father and mother with another person, or who has one of them only. In the latter case he is more definitely called a half brother, or brother of the half blood.

One related or closely united to another by some common tie or interest, as of rank, profession, membership in a society, toil, suffering, etc.; - used among judges, clergymen, monks, physicians, lawyers, professors of religion, etc.

One who, or that which, resembles another in distinctive qualities or traits of character.

To make a brother of; to call or treat as a brother; to admit to a brotherhood.

A male with the same parents as someone else;

A male person who is a fellow member (of a fraternity or religion of other group);

A close friend who accompanies his buddies in their activities

Used as a term of address for those male persons engaged in the same movement;

(Roman Catholic Church) a title given to a monk and used as form of address;