What does 兄さん mean?
兄さん is a Japanese noun meaning “older brother; elder brother” in English. It can also be translated as “young man” depending on context. It is written as 兄さん in kanji, にいさん in hiragana, and niisan in romaji. This word is part of JLPT N4 vocabulary.
Example sentence
兄さんはよくおなりだと思いますが。
I hope your brother is better.