(1) 兄弟，弟，兄(male child of the same parents)[C]：Do you have any～s? 你有兄弟(兄或弟)吗? one's elder/younger～哥哥/弟弟;one's husband's～丈夫的兄弟;He's been like a～to me.他一直像我的亲兄弟一样。the Smith～s/the～s Smith史密斯兄弟;

(2) (男)同事(志，僚)(male fellow member of the same group， society， profession， etc)[C]：one's～doctors/officers/judges 医务界同行/军队同僚/法院同事;～s in arms战友;All men are our～s.天下男人都是我们的兄弟! We must fight for our rights，～s! 弟兄们，我们应该争取我们的权利! He is a fraternity～of mine.他是我的一个哥们儿。〖同〗fellowman，comrade，companion，colleague;

(3) 男教友;修士(male member of a religious organization)[C]：Christian B～(基督教)修士;B～Martin马丁修士;The brethren met every week.男教友们每周会面。〖同〗monk;

→′brotherly adj 兄弟(般)的;′brotherliness n 手足之情;′brotherless adj 无兄弟的; ′brotherhood n 兄弟关系;同仁(志)之情;′brother-in-law n 夫或妻的兄弟;′stepbrother n 异父(母)兄弟;′halfbrother n 异父(母)兄弟;

【注意】the brothers Smith 和 the Smith brothers 都对，但前者是旧用法，现代越来越多用后者。sisters也是放在姓后，如：the Bronte sisters。