This is the 8032nd most frequent Japanese word.
姉さん
Older sister; a respectful or familiar term for an older woman.
The word '姉さん' here refers to one's own elder sister, typically used in a familial and endearing sense.
姉さんはいつも優しく助けてくれる。
(My) elder sister is always kind and helpful.
'姉さん' is used here as a respectful term to address a woman, often in informal or intimate contexts.
あの人を姉さんと呼んでもいいですか。
Can I call that person 'elder sister'?
In this case, '姉さん' directly addresses the speaker's elder sister as part of a direct conversation.