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n. pl. broth·ers
1. A male having the same parents as another or one parent in common with another.
2. pl. also brethren (brĕth′rən) One who shares a common ancestry, allegiance, character, or purpose with another or others, especially:
a. A kinsman.
b. A fellow man.
c. A fellow member, as of a fraternity, trade union, or panel of judges on a court.
d. A close male friend; a comrade.
e. A fellow African-American man or boy.
3. pl. also brethren Something, such as a corporation or institution, that is regarded as a member of a class: "A station that ... relies on corporate contributions or advertising to survive runs the risk of becoming virtually indistinguishable from its commercial brethren" (W. John Moore).
a. Abbr. Br. or Bro. A lay member of a religious order of men.
b. pl. also brethren A fellow member of the Christian church.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.