What does お兄さん mean?
お兄さん is a Japanese noun meaning “(someone else's) older brother (formal)” in English. It can also be translated as “young man” depending on context. It is written as お兄さん in kanji, おにいさん in hiragana, and oniisan in romaji. This word is part of JLPT N5 vocabulary.
Example sentence
彼のお兄さんは有名なサッカーの選手です。
His brother is a famous soccer player.