noun
elder daughter; older daughter
Refers to one's own elder daughter or the elder daughter in a family. Not used for someone else's elder sister.
私の姉娘は来年大学を卒業します。
My elder daughter will graduate from university next year.
姉娘が料理を手伝ってくれた。
My older daughter helped me with the cooking.
Compound of 姉 (ane, 'elder sister') and 娘 (musume, 'daughter'). The exact historical derivation is uncertain, but the spelling is conventionally associated with the meaning 'elder daughter'.