noun
Familiar, affectionate term for one's own older brother, similar to お兄ちゃん but more casual. Used within the family or when speaking about one's brother to close friends.
See also: お兄ちゃん
兄ちゃん、宿題手伝ってくれる？
Big brother, can you help me with my homework?
うちの兄ちゃんは今大学生なんだ。
My older brother is a university student now.
noun
Informal, sometimes slightly rough way to address or refer to a young man, especially by an older person. Can sound friendly or condescending depending on tone. The reading あんちゃん is also used for this sense, often with a more rough or dialectal feel.
See also: お兄ちゃん
兄ちゃん、ちょっと道を教えてくれないか。
Hey, young man, can you tell me the way?
あの兄ちゃん、なかなかやるな。
That lad is pretty good, isn't he?