兄弟【きょうだい】
siblings, brothers and sisters, brothers, siblings-in-law, brothers-in-law, sisters-in-law, mate, friend
兄さん【にいさん】
older brother, elder brother, brother (as older-brother figure in friendly and or work relationship), young man, buddy, fella, laddie
兄貴【あにき】
elder brother, one's senior, older man, man older than oneself
お兄さん【おにいさん】
older brother, elder brother, young man, buddy, fella, laddie
お兄ちゃん【おにいちゃん】
(one's) older brother, lad, sonny
兄ちゃん【にいちゃん】
(one's) older brother, young man, sonny, lad
兄上【あにうえ】
older brother
兄様【にいさま】
older brother
義兄【ぎけい】
brother-in-law (spouse's older brother or older sister's husband), older stepbrother
兄妹【けいまい】
older brother and younger sister
実兄【じっけい】
biological older brother
長兄【ちょうけい】
eldest brother
兄弟子【あにでし】
senior pupil (of the same master), senior disciple, senior student, senior member
兄姉【けいし】
brother and sister
親兄弟【おやきょうだい】
parents and siblings, one's relatives
従兄【じゅうけい】
cousin (older male)