big sister

American  

noun

1. an elder sister.

2. (sometimes initial capital letters) a woman who individually or as a member of an organized group undertakes to sponsor or assist a girl in need of help or guidance.

3. (sometimes initial capital letters) a young woman in the junior or senior class in college who advises a young woman in the freshman class on studies, social activities, etc., often as a part of a sorority program.

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Example Sentences

"I loved her to bits, she was my big sister who did everything for all of us."

From BBC • Mar. 10, 2026

What she found was that the relationship went beyond business; she sees her agent as part negotiator, part therapist, part big sister.

From The Wall Street Journal • Mar. 4, 2026

She paid tribute to Sakamoto who is affectionately called "big sister" by her teammates.

From Barron's • Feb. 20, 2026

She is like the big sister to everyone - she knows what to do in stressful situations and handles things so smoothly.

From BBC • Sep. 20, 2025

My big sister is not good at this whole game, even though she’s spent a year away at college.

From "Pride" by Ibi Zoboi