兄

兄

お兄さん

(1)(hon) older brother/elder brother/ (2)(vocative) young man/buddy/fella/laddie

御兄さん

兄貴

(1)(fam)(hon) elder brother/ (2) one's senior/ (3) older man/man older than oneself

兄さん

(1)(hon) older brother/elder brother/ (2) brother (as older-brother figure in friendly and or work relationship) / (3)(vocative) young man/buddy/fella/laddie

お兄ちゃん

(1)(fam) familiar form of older brother/ (2)(fam) form of address for young adult male/mister