An elder sister; a female sibling who is older.

An experienced female who holds a higher position, often in an organizational or educational context.

बड़ी बहन

English Usage: My senior sister always helps me with my homework.

Hindi Usage: मेरी बड़ी बहन हमेशा मेरी होमवर्क में मदद करती है।

An older female relative, not necessarily a sibling.

बड़ी महिला रिश्तेदार

English Usage: She treated me like a senior sister even though we were not related.

Hindi Usage: उसने मुझे बड़ी बहन की तरह माना, हालांकि हम रिश्तेदार नहीं थे।