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

She has done so without being hounded by her big sister.

From Los Angeles Times • Mar. 23, 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

Affectionately called "big sister" by her teammates, she is leading a new generation of Japanese stars including Nakai, 17, and Chiba, 20.

From Barron's • Feb. 17, 2026

Zoe Atkin, one of Britain's biggest medal hopes at these Games, begins her quest to emulate big sister Izzy and win an Olympic medal.

From BBC • Feb. 2, 2026

“I saw my big sister writing one last night. She wrote the name upside down and then put a big red X over it. She said that’s what the court used to do to criminals.”

From "Red Scarf Girl: A Memoir of the Cultural Revolution" by Ji-li Jiang