兄

兄妹 xiōngmèi #7,972

brother and sister (specifically older brother and younger sister) / siblings (male and female)

兄弟 xiōngdì HSK 4 #400

brothers / bro (informal)

兄长 xiōngzhǎng #14,883

elder brother / term of respect for a man of similar age

小兄弟 xiǎoxiōngdì #9,655

young man (friendly address) / little brother / buddy

弟兄 dìxiong #5,654

brothers / brethren / buddy

老兄 lǎoxīōng #709

buddy / pal / bro / old chap

堂兄 tángxiōng #9,717

older male patrilineal cousin (father's brother's son who is older than you)

伯 bó #4,237

uncle (father's elder brother) / earl; count / senior; elder

堂兄弟 tángxiōngdì #22,669

paternal male cousins / father's brother's sons / male cousins on the father's side (same surname)

仁兄 rénxiōng #23,400

my dear friend (honorific written address to a male equal) / good brother (respectful form of address)