An older sister (polite or familiar form). Used to address or refer to one's elder sister.
姉さん、手伝ってくれる？
Sis, can you help me?
うちの姉さんは料理が上手だ。
My older sister is good at cooking.
彼は姉さんをとても尊敬している。
He respects his older sister very much.
A vocative for a young woman — a familiar way to call or address a young lady (similar to 'miss').
姉さん、そこ空いてるよ。
Miss, that seat is free.
店の人が姉さんと呼んで彼女に注文を聞いた。
The shopkeeper called her 'sister' (miss) and took her order.
Used to refer to a woman (often a senior or bossy woman) such as a waitress, madam, or an older woman in a workplace — often written 姐さん.
居酒屋の姐さんが新人に指示を出している。
The madam of the izakaya is giving orders to the newcomer.
あの姐さんに頼めば、なんとかしてくれるよ。
If you ask that woman (the bossy lady), she'll do something about it.
A respectful form of address (ma'am) used in contexts like the geisha world to refer to a superior female.
芸者は師匠のことを姐さんと呼んだ。
The geisha called her master 'nee-san' (a respectful title).
その店では先輩を姐さんと呼ぶ習慣がある。
In that shop, there is a custom of calling seniors 'nee-san'.